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Purpose: The primary aims of this study were to examine the effects of 9 weeks of aerobic training, comprising three 30‐min sessions per week, on V̇O2max, inhibitory control, and plasma brain‐derived neurotrophic factor (BDNF) levels among adolescents aged 16–19 years. Methods: One hundred twenty‐one untrained or recreationally active adolescents from a Danish high school were enrolled in the study, with 58 females (17.8 ± 0.8 years) and 27 males (18.0 ± 0.9 years) completing it. Participants were randomly divided into three groups performing aerobic training at either moderate‐intensity (MIT: 60%–70% heart rate reserve [HRR]) or high‐intensity (HIT: 80%–100% HRR) or a passive control group (CON) continuing their habitual lifestyle. Both the training groups exercised for 3×30 min per week for 9 weeks using a combination of cycling and running. Before and after the intervention period maximal oxygen uptake (V̇O2max) and the primary outcomes (inhibitory control measured by a modified flanker task, and resting plasma levels of BDNF) were evaluated. Results: After the intervention period, the HIT group demonstrated a larger increase in V̇O2max compared to both the CON and MIT groups, while no significant effects were observed on inhibitory control or plasma BDNF levels in any training group. However, compared to the CON group, the HIT group exhibited a tendency for greater improvement in the flanker interference score (accuracy), attributable to enhanced accuracy on the incongruent stimuli from pre to post. Conclusion: Aerobic training in adolescents increased cardiorespiratory fitness in an intensity‐dependent manner, but no clear effects were observed on neither inhibitory control nor resting plasma BDNF levels. Clinical Trial Registration: ClinicalTrials.gov: NCT02075944. [ABSTRACT FROM AUTHOR]

Fatigue resistance is vital for success in elite road cycling, as repeated, intense efforts challenge the athletes' ability to sustain peak performance throughout prolonged races. The present study combined recurrent performance testing and physiological measures during 6 h simulated racing with laboratory testing to investigate factors influencing fatigue resistance. Twelve male national elite cyclists (25 ± 3 years; 76 ± 6 kg and VO2max of 5.2 ± 0.5 L/min) completed incremental power and maximal fat oxidation tests. Subsequently, they underwent field testing with physiological measures and fatigue responses evaluated through peak sprint power and 5 km time trial (TT) testing after 0, 2, 4, and 6 h of exercise. Peak power declined from 1362 ± 176 W in first sprint to 1271 ± 152 W after 2 h (p < 0.01) and then stabilized. In contrast, TT mean power gradually declined from 412 ± 38 W in the first TT to 384 ± 41 W in the final trial, with individual losses ranging from 2% to 14% and moderately correlated (r2 = 0.45) to accumulated exercise time above lactate threshold. High carbohydrate intake (~90 g/h) maintained blood glucose levels, but post‐TT [lactate] decreased from 15.1 ± 2 mM to 7.1 ± 2.3 mM, while fat oxidation increased from 0.7 ± 0.3 g/min at 0 h to 1.1 ± 0.1 g/min after 6 h. The study identifies fatigue patterns in national elite cyclists. Peak sprint power stabilized after an initial impairment from 0 to 2 h, while TT power gradually declined over the 6 h simulated race, with increased differentiation in fatigue responses among athletes. [ABSTRACT FROM AUTHOR]

Passive hamstring stiffness varies proximo‐distally, resulting in inhomogeneous tissue strain during stretching that may affect localized adaptations and risk of muscle injuries. The purpose of the present study was to determine the acute and chronic effects of static stretching (SS) on intramuscular hamstring stiffness. Thirty healthy active participants had acute changes in passive biceps femoris (BF), semimembranosus (SM), and semitendinosus (ST) stiffness measured at 25% (proximal), 50% (middle), and 75% (distal) muscle length, using shear‐wave elastography, immediately after SS. Participants then completed 4 weeks of either a SS intervention (n = 15) or no intervention (CON, n = 15) with stiffness measured before and after the interventions. The acute and chronic effects of SS were compared between anatomical regions and between regions on the basis of their relative stiffness pre‐intervention. Acutely, SS decreased stiffness throughout the BF and SM (p ≤ 0.05) but not the ST (p = 0.326). However, a regional effect of stretching was observed for SM and ST with greater reduction in stiffness occurring in stiffer muscular regions (p = 0.001–0.013). Chronically, SS increased BF and ST (p < 0.05), but not SM (p = 0.422) stiffness compared with CON, but no regional effect of stretching was observed in any muscle (p = 0.361–0.833). SS resulted in contrasting acute and chronic effects, acutely decreasing stiffness in stiffer regions while chronically increasing stiffness. These results indicate that the acute effects of SS vary along the muscle's length on the basis of the relative stiffness of the muscle and that acute changes in stiffness from SS are unrelated to chronic adaptations. [ABSTRACT FROM AUTHOR]

Overuse injuries, which have a high prevalence in sport, are suggested to result in different affective responses in comparison to traumatic injuries. Affects may also reciprocally act as risk factors for overuse injury. The aim of this study was to examine the associations between overuse injury and affects within a longitudinal follow‐up design. Competitive athletes (N = 149) of various sports and levels of competition completed the Positive and Negative Affect Schedule (PANAS) and the Oslo Sports Trauma Research Centre Overuse injury questionnaire (OSTRC‐O) once a week over 10 consecutive weeks. Bivariate unconditional latent curve model analyses with structured residuals were performed to evaluate the associations within and across weeks between OSTRC‐O severity score and affects. Results indicated that OSTRC‐O severity score and positive affects (PA) had a statistically significant negative within‐week relation (r = −24.51, 95% CI = [−33.9, −15.1], p < 0.001). Higher scores of overuse injury were significantly related to lower levels of PA across weeks (ß = −0.02, 95% CI = [−0.04, −0.001], p = 0.044), while the reciprocal effect of PA on overuse injury was not significant (ß = −0.13, 95% CI = [−0.52, 0.26], p = 0.51). No statistically significant association was observed between OSTRC‐O severity score and negative affects, neither within nor across weeks. Our findings suggest that overuse injury may have adverse psychological consequences on the long run through lessened PA and address the need for providing sustainable psychological support focusing upon such PA when working with athletes experiencing overuse injury. [ABSTRACT FROM AUTHOR]

The effects of a 12‐week gait retraining program on the adaptation of the medial gastrocnemius (MG) and muscle‐tendon unit (MTU) were investigated. 26 runners with a rearfoot strike pattern (RFS) were randomly assigned to one of two groups: gait retraining (GR) or control group (CON). MG ultrasound images, marker positions, and ground reaction forces (GRF) were collected twice during 9 km/h of treadmill running before and after the intervention. Ankle kinetics and the MG and MTU behavior and dynamics were quantified. Runners in the GR performed gradual 12‐week gait retraining transitioning to a forefoot strike pattern. After 12‐week, (1) ten participants in each group completed the training; eight participants in GR transitioned to non‐RFS with reduced foot strike angles; (2) MG fascicle contraction length and velocity significantly decreased after the intervention for both groups, whereas MG forces increased after intervention for both groups; (3) significant increases in MTU stretching length for GR and peak MTU recoiling velocity for both groups were observed after the intervention, respectively; (4) no significant difference was found for all parameters of the series elastic element. Gait retraining might potentially influence the MG to operate at lower fascicle contraction lengths and velocities and produce greater peak forces. The gait retraining had no effect on SEE behavior and dynamics but did impact MTU, suggesting that the training was insufficient to induce mechanical loading changes on SEE behavior and dynamics. [ABSTRACT FROM AUTHOR]

Background: Quantitative ultrasound (QUS) techniques are new diagnostic tools able to identify changes in structural and material properties of the investigated tissue. For the first time, we evaluated the capability of QUS techniques in determining the in vivo transient changes in knee joint cartilage after a stressful task. Methods: An ultrasound scanner collecting B‐mode and radiofrequency data simultaneously was used to collect data from the femoral cartilage of the right knee in 15 participants. Cartilage thickness (CTK), ultrasound roughness index (URI), average magnitude ratio (AMR), and Nakagami parameters (NA) were evaluated before, immediately after and every 5 min up to 45 min a stressful task (30 min of running on a treadmill with a negative slope of 5%). Results: CTK was affected by time (main effect: p < 0.001). Post hoc test showed significant differences with CTK at rest, which were observed up to 30 min after the run. AMR and NA were affected by time (p < 0.01 for both variables), while URI was unaffected by it. For AMR, post hoc test showed significant differences with rest values in the first 35 min of recovery, while NA was increased compared to rest values in all time points. Conclusion: Data suggest that a single running trial is not able to modify the integrity of the femoral cartilage, as reported by URI data. In vivo evaluation of QUS parameters of the femoral cartilage (NA, AMR, and URI) are able to characterize changes in cartilage properties over time. [ABSTRACT FROM AUTHOR]

Intense physical exercise is known to increase cardiac biomarkers; however, it is unclear, whether this phenomenon is physiological, or if it indicates myocardial tissue injury. The aim of our study was to investigate the effects of seven consecutive days of excessive endurance exercise on continuous assessment of cardiac biomarkers, function, and tissue injury. During a 7‐day trail‐running competition (Transalpine Run, distance 267.4 km, altitude ascent/descent 15556/14450 m), daily blood samples were obtained for cardiac biomarkers (hs‐TnT, NT‐proBNP, and suppression of tumorigenicity‐2 protein (ST2)) at baseline, after each stage and 24–48 h post‐race. In addition, echocardiography was performed every second day, cardiac magnetic resonance imaging (CMR) before (n = 7) and after (n = 16) the race. Twelve (eight males) out of 17 healthy athletes finished all seven stages (average total finish time: 43 ± 8 h). Only NT‐proBNP increased significantly (3.6‐fold, p = 0.009) during the first stage and continued to increase during the race. Hs‐TnT revealed an incremental trend during the first day (2.7‐fold increase, p = 0.098) and remained within the pathological range throughout the race. ST2 levels did not change during the race. All cardiac biomarkers completely returned to physiological levels post‐race. NT‐proBNP kinetics correlated significantly with mild transient reductions in right ventricular function (assessed by TAPSE, tricuspid annular plane systolic function; r = −0.716; p = 0.014). No significant echocardiographic changes in LV dimensions, LV function, or relevant alterations in CMR were observed post‐race. In summary, this study shows that prolonged, repetitive, high‐volume exercise induced a transient, significant increase in NT‐proBNP associated with right ventricular dysfunction without corresponding left ventricular functional or structural impairment. [ABSTRACT FROM AUTHOR]

Objective: To explore how sports injury epidemiological outcomes (i.e., prevalence, average prevalence, incidence, burden, and time to first injury) vary depending on the response rates to a weekly online self‐reported questionnaire for athletes. Methods: Weekly information on athletics injuries and exposure from 391 athletics (track and field) athletes was prospectively collected over 39 weeks (control group of the PREVATHLE randomized controlled trial) using an online self‐reported questionnaire. The data were used to calculate sports injury epidemiological outcomes (i.e., prevalence, average prevalence, incidence, burden, and time to first injury) for sub‐groups with different minimum individual athletes' response rates (i.e., from at least 100%, at least 97%, at least 95%, ... to at least 0% response rate). We then calculated the relative variation between each sub‐group and the sub‐group with a 100% response rate as a reference. A substantial variation was considered when the relative variation was greater than one SD or 95% CI of the respective epidemiological outcome calculated in the sub‐group with a 100% response rate. Results: Of 15 249 expected weekly questionnaires, 7209 were completed and returned, resulting in an overall response rate of 47.3%. The individual athletes' response rates ranged from 0% (n = 51) to 100% (n = 100). The prevalence, average weekly prevalence, and time to first injury only varied substantially for the sub‐groups below a 5%, 10% and 18% minimum individual response rate, respectively. The incidence and injury burden showed substantial variations for all sub‐groups with a response rate below 100%. Conclusions: Epidemiological outcomes varied depending on the minimum individual athletes' response rate, with injury prevalence, average weekly prevalence, and time to first injury varying less than injury incidence and injury burden. This highlights the need to take into account the individual response rate when calculating epidemiological outcomes, and determining the optimal study‐specific cut‐offs of the minimum individual response rate needed. [ABSTRACT FROM AUTHOR]

Ankle inversion orientation and peroneal activation insufficiency may contribute to lateral ankle sprains during landing in chronic ankle instability (CAI); however, how anticipation alters these factors is neglected. This study aimed to assess the impact of anticipation on joint orientation and muscle activity during landing in individuals with CAI. Fifteen participants with CAI and 15 healthy participants (control) were recruited to perform single‐leg landings after bilateral countermovement jumps when the landing limb was specified before (planned) or after (unplanned) take‐off. Joint angle (hip, knee, and ankle) and electromyography (gluteus medius, rectus femoris, biceps femoris, gastrocnemius lateral head, tibialis anterior, and peroneal longus) were collected and analyzed with 2 (groups) × 2 (conditions) statistical parametric mapping ANOVA. In the unplanned condition, the CAI group demonstrated a less plantarflexed (maximum difference [MD] = 9.5°, p = 0.047) and more inverted ankle joint (MD = 4.1°, p < 0.001) before ground contact, along with lower peroneal activity at ground contact compared to the control group (MD = 28.9% of peak activation, p < 0.001). No significant differences between groups were observed in the planned condition. In conclusion, anticipation may mask jump landing deficits in people with CAI, including inverted ankle orientation and reduced peroneus longus activity pre‐ and post‐landing, which were observed exclusively in unplanned landings. Clinicians and researchers need to recognize the impact of anticipation on apparent landing deficits and consider the implications for injury prevention and rehabilitation strategies. [ABSTRACT FROM AUTHOR]

Background: An increasing number of commercially available wearables provide real‐time feedback on running biomechanics with the aim to reduce injury risk or improve performance. Objective: Investigate whether real‐time feedback by wearable insoles (ARION) alters running biomechanics and improves running economy more as compared to unsupervised running training. We also explored the correlation between changes in running biomechanics and running economy. Methods: Forty recreational runners were randomized to an intervention and control group and performed ~6 months of in‐field training with or without wearable‐based real‐time feedback on running technique and speed. Running economy and running biomechanics were measured in lab conditions without feedback pre and post intervention at four speeds. Results: Twenty‐two individuals (13 control, 9 intervention) completed both tests. Both groups significantly reduced their energetic cost by an average of −6.1% and −7.7% for the control and intervention groups, respectively. The reduction in energy cost did not significantly differ between groups overall (−0.07 ± 0.14 J∙kg∙m−1, −1.5%, p = 0.63). There were significant changes in spatiotemporal metrics, but their magnitude was minor and did not differ between the groups. There were no significant changes in running kinematics within or between groups. However, alterations in running biomechanics beyond typical session‐to‐session variation were observed during some in‐field sessions for individuals that received real‐time feedback. Conclusion: Alterations in running biomechanics as observed during some in‐field sessions for individuals receiving wearable‐based real‐time feedback did not result in significant differences in running economy or running biomechanics when measured in controlled lab conditions without feedback. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study was to investigate whether carbohydrate utilization is altered during exercise in overreached endurance athletes and examine the utility of continuous glucose monitors (CGM) to detect overreaching status. Methods: Eleven endurance athletes (M:8, F:3) completed a 5‐week training block consisting of 1 week of reduced training (PRE), 3 weeks of high‐intensity overload training (POST), and 1 week of recovery training (REC). Participants completed a Lamberts and Lambert Submaximal Cycling Test (LSCT) and 5 km time‐trial at PRE, POST, and REC time points, 15 min following the ingestion of a 50 g glucose beverage with glucose recorded each minute via CGM. Results: Performance in the 5 km time‐trial was reduced at POST (∆‐7 ± 10 W, p = 0.04, ηp2 = 0.35) and improved at REC (∆12 ± 9 W from PRE, p = 0.01, ηp2 = 0.66), with reductions in peak lactate (∆‐3.0 ± 2.0 mmol/L, p = 0.001, ηp2 = 0.71), peak HR (∆‐6 ± 3 bpm, p < 0.001, ηp2 = 0.86), and Hooper‐Mackinnon well‐being scores (∆10 ± 5 a.u., p < 0.001, ηp2 = 0.79), indicating athletes were functionally overreached. The respiratory exchange ratio was suppressed at POST relative to REC during the 60% (POST: 0.80 ± 0.05, REC: 0.87 ± 0.05, p < 0.001, ηp2 = 0.74), and 80% (POST: 0.93 ± 0.05, REC: 1.00 ± 0.05, p = 0.003, ηp2 = 0.68) of HR‐matched submaximal stages of the LSCT. CGM glucose was reduced during HR‐matched submaximal exercise in the LSCT at POST (p = 0.047, ηp2 = 0.36), but not the 5 km time‐trial (p = 0.07, ηp2 = 0.28) in overreached athletes. Conclusion: This preliminary investigation demonstrates a reduction in CGM‐derived glucose and carbohydrate oxidation during submaximal exercise in overreached athletes. The use of CGM during submaximal exercise following standardized nutrition could be employed as a monitoring tool to detect overreaching in endurance athletes. [ABSTRACT FROM AUTHOR]

The neural drive to the muscle is the primary determinant of the rate of force development (RFD) in the first 50 ms of a rapid contraction. It is still unproven if repetitive rapid contractions specifically impair the net neural drive to the muscles. To isolate the fatiguing effect of contraction rapidity, 17 male adult volunteers performed 100 burst‐like (i.e., brief force pulses) isometric contractions of the knee extensors. The response to electrically‐evoked single and octet femoral nerve stimulation was measured with high‐density surface electromyography (HD‐sEMG) from the vastus lateralis and medialis muscles. Root mean square (RMS) of each channel of HD‐sEMG was normalized to the corresponding M‐wave peak‐to‐peak amplitude, while muscle fiber conduction velocity (MFCV) was normalized to M‐wave conduction velocity to compensate for changes in sarcolemma properties. Voluntary RFD 0–50 ms decreased (d = −0.56, p < 0.001) while time to peak force (d = 0.90, p < 0.001) and time to RFDpeak increased (d = 0.56, p = 0.034). Relative RMS (d = −1.10, p = 0.006) and MFCV (d = −0.53, p = 0.007) also decreased in the first 50 ms of voluntary contractions. Evoked octet RFD 0–50 ms (d = 0.60, p = 0.020), M‐wave amplitude (d = 0.77, p = 0.009) and conduction velocity (d = 1.75, p < 0.001) all increased. Neural efficacy, i.e., voluntary/octet force ratio, largely decreased (d = −1.50, p < 0.001). We isolated the fatiguing impact of contraction rapidity and found that the decrement in RFD, particularly when calculated in the first 50 ms of muscle contraction, can mainly be explained by a decrease in the net neural drive. [ABSTRACT FROM AUTHOR]

Objective: To describe the epidemiology of quadriceps muscle strain injury (QMSI) in elite Australian Football League (AFL) players, explore recovery milestones and determine whether recovery is impacted by factors such as injury type (index vs. re‐injury), the primary muscle injured and the mechanism of injury. Measures: All QMSI data reported to the Soft Tissue Injury Registry of the AFL from the 2014 to 2020 seasons were evaluated. Player demographic data, circumstances of injury, MRI reports and recovery outcomes following injury were extracted. Descriptive statistics and frequency distributions are presented. Recovery outcomes for injury type, primary muscle injured and the mechanism of injury were compared using univariate analyses. Results: There were 164 QMSIs from 122 players reported (134 index; 30 re‐injuries). Almost all (91.3%) QMSIs involved the rectus femoris. Half (48.4%) of the QMSIs occurred during kicking and most commonly affected the dominant kicking leg (72%). The majority occurred at training (64.6%). All re‐injuries involved the rectus femoris, most occurred from kicking (63.0%) and within 6 months of the preceding injury (70%). The mean return to play (RTP) time was 25.4 days (95%CI = 22.6–28.2) and rectus femoris injuries took around 14 days longer to RTP than vastii injuries (p = 0.001). QMSIs with a kicking mechanism took the longest to RTP of all injury mechanisms. Conclusion: In AFL players, QMSIs occur mostly in the dominant leg from a kicking mechanism. Rectus femoris injuries are more prevalent and result in longer RTP time frames. Re‐injuries exclusively involved the rectus femoris, primarily from kicking. [ABSTRACT FROM AUTHOR]

Background: There is a lack of a methodological standard to process accelerometer data to measures of physical activity, which impairs data quality and comparability. This study investigated the effect of different combinations of settings of multiple processing components, on the measure of physical activity and the association with measures of cardiometabolic health in an unselected population of middle‐aged individuals. Methods: Free‐living hip accelerometer data, aerobic fitness, body mass index, HDL:total cholesterol ratio, blood glucose, and systolic blood pressure were achieved from 4391 participants 50–64 years old included in The Swedish CArdioPulmonary bioImage Study (SCAPIS) baseline measurement (cross‐sectional). Lab data were also included for calibration of accelerometers to provide comparable measure of physical activity intensity and time spent in different intensity categories, as well as to enhance understanding. The accelerometer data processing components were hardware recalibration, frequency filtering, number of accelerometer axes, epoch length, wear time criterium, time composition (min/24 h vs. % of wear time). Partial least regression and ordinary least regression were used for the association analyses. Results: The setting of frequency filter had the strongest effect on the physical activity intensity measure and time distribution in different intensity categories followed by epoch length and number of accelerometer axes. Wear time criterium and recalibration of accelerometer data were less important. The setting of frequency filter and epoch length also showed consistent important effect on the associations with the different measures of cardiometabolic health, while the effect of recalibration, number of accelerometer axes, wear time criterium and expression of time composition was less consistent and less important. There was a large range in explained variance of the measures of cardiometabolic health depending on the combination of processing settings, for example, 12.1%–20.8% for aerobic fitness and 5.8%–14.0% for body mass index. Conclusions: There was a large variation in the physical activity intensity measure and the association with different measures of cardiometabolic health depending on the combination of settings of accelerometer data processing components. The results provide a fundament for a standard to process hip accelerometer data to assess the physical activity in middle‐aged populations. [ABSTRACT FROM AUTHOR]

Background: Ethylene and vinyl acetate (EVA) and polyether block amide (PEBA) are recently the most widely used materials for advanced footwear technology (AFT) that has been shown to improve running economy (RE). This study investigated the effects of these midsole materials on RE and biomechanics, in both fresh and worn state (after 450 km). Methods: Twenty‐two male trained runners participated in this study. Subjects ran four 4‐min trials at 13 km‧h−1 with both fresh EVA and PEBA AFT and with the same models with 450 km of wear using a randomized crossover experimental design. We measured energy cost of running (W/kg), spatiotemporal, and neuromuscular parameters. Results: There were significant differences in RE between conditions (p = 0.01; n2 = 0.17). There was a significant increase in energy cost in the worn PEBA condition compared with new (15.21 ± 1.01 and 14.87 ± 0.99 W/kg; p < 0.05; ES = 0.54), without differences between worn EVA (15.13 ± 1.14 W/kg; p > 0.05), and new EVA (15.15 ± 1.13 w/kg; ES = 0.02). The increase in energy cost between new and worn was significantly higher for the PEBA shoes (0.32 ± 0.38 W/kg) but without significant increase for the EVA shoes (0.06 ± 0.58 W/kg) (p < 0.01; ES = 0.51) with changes in step frequency and step length. The new PEBA shoes had lower energy cost than the new EVA shoes (p < 0.05; ES = 0.27) with significant differences between conditions in contact time. Conclusion: There is a clear RE advantage of incorporating PEBA versus EVA in an AFT when the models are new. However, after 450 km of use, the PEBA and EVA shoes had similar RE. [ABSTRACT FROM AUTHOR]

Purpose: Jump‐landing exercises are often performed during the rehabilitation of Achilles tendon (AT) injuries. However, the factors that affect the AT force (ATF) during landing are unclear. This study aimed to determine the kinematics and ground reaction force (GRF) variables associated with the peak ATF during a drop vertical jump (DVJ). Methods: The landing phase of DVJ was evaluated in 101 healthy participants (46 males, age: 21.2 ± 1.4 years old) using a three‐dimensional motion analysis system with two force plates. ATF was estimated from the ankle flexion angle and moment. Univariate and multivariate regression analyses were performed with the peak ATF as the dependent variable. The vertical GRF (VGRF), center of pressure (COP), forward trunk leaning, hip/knee/ankle joint angles at peak ATF, and sex were used as independent variables. Results: In the univariate regression analysis, larger VGRF (β = 0.813), more anterior COP position (β = 0.214), smaller knee flexion (β = −0.251) and adduction (β = −0.252), smaller hip flexion (β = −0.407), smaller forward trunk lean (β = −0.492), and male sex (β = −0.282) were significantly associated with a larger peak ATF. Multivariate analysis revealed that larger VGRF (β = 1.018), more anterior COP position (β = 0.320), a larger knee (β = 0.442), and smaller hip flexion (β = −0.205) were associated with the larger peak ATF. Conclusions: The VGRF, COP position, and knee and hip flexion were independently associated with ATF. Modifying these factors may be useful in managing tendon loading during jump‐landing exercises. [ABSTRACT FROM AUTHOR]

Introduction: When performing an exercise or a functional test, pain that is evoked by movement or muscle contraction could be a stronger stimulus for changing how individuals move compared to tonic pain. We investigated whether the decrease in muscle force production is larger when experimentally‐induced knee pain is directly associated to the torque produced (movement‐evoked) compared to a constant painful stimulation (tonic). Methods: Twenty‐one participants performed three isometric knee extension maximal voluntary contractions without pain (baseline), during pain, and after pain. Knee pain was induced using sinusoidal electrical stimuli at 10 Hz over the infrapatellar fat pad, applied continuously or modulated proportionally to the knee extension torque. Peak torque and contraction duration were averaged across repetitions and normalized to baseline. Results: During tonic pain, participants reported lower pain intensity during the contraction than at rest (p < 0.001), whereas pain intensity increased with contraction during movement‐evoked pain (p < 0.001). Knee extension torque decreased during both pain conditions (p < 0.001), but a larger reduction was observed during movement‐evoked compared to tonic pain (p < 0.001). Participants produced torque for longer during tonic compared to movement‐evoked pain (p = 0.005). Conclusion: Our results indicate that movement‐evoked pain was a more potent stimulus to reduce knee extension torque than tonic pain. The longer contraction time observed during tonic pain may be a result of a lower perceived pain intensity during muscle contraction. Overall, our results suggest different motor adaptation to tonic and movement‐evoked pain and support the notion that motor adaptation to pain is a purposeful strategy to limit pain. This mechanistic evidence suggests that individuals experiencing prevalently tonic or movement‐evoked pain may exhibit different motor adaptations, which may be important for exercise prescription. [ABSTRACT FROM AUTHOR]

Sex differences in the cardiorespiratory and hemodynamic response to exercise exist due to differences in heart size, blood volume, and hemoglobin mass, eliciting higher maximal oxygen uptake (VO2max) in men versus women. Data are equivocal whether sex differences in training responsiveness occur. This study investigated potential sex differences in the hemodynamic response (stroke volume (SV) and cardiac output (CO)) to high‐intensity interval exercise (HIIE). Habitually active men (n = 15) and women (n = 13) underwent VO2max testing, followed by three HIIE sessions consisting of the 4 × 4, 10 × 1, and reduced exertion high‐intensity training (REHIT), whose order was randomized. During exercise, oxygen uptake (VO2) and hemodynamic responses were determined. Results showed no sex difference in peak relative VO2 (p = 0.263), CO (p = 0.277), or SV (p = 0.116), although absolute values were higher in men (p < 0.05). Peak absolute (127.3 ± 20.6 vs. 115.2 ± 16.6 mL/beat, p = 0.004, d = 0.66) and relative SV (111.0 ± 15.5 vs. 100.7 ± 11.1% max, p = 0.005, d = 0.78) were higher with REHIT versus 4 × 4. No sex differences in mean relative VO2, CO, or SV occurred (p > 0.05). Data showed lower mean VO2 during REHIT versus 4 × 4 (59.3 ± 6.8 vs. 65.8 ± 5.8 %VO2max, p < 0.001, d = 1.05) and 10 × 1 (59.3 ± 6.8 vs. 69.1 ± 7.4 %VO2max, p < 0.001, d = 1.4). Mean CO was lower in REHIT than 10 × 1 (79.8 ± 8.6 vs. 84.0 ± 7.4% max, p = 0.012, d = 0.53). Previously reported differences in VO2max response to HIIE may not be due to unique hemodynamic responses. [ABSTRACT FROM AUTHOR]

Objective: The aim of the present study was to examine whether 10‐20‐30 training (consecutive 1‐min intervals consisting of 30 s at low‐speed, 20 s at moderate‐speed, and 10 s at high‐speed), performed with submaximal effort during the 10‐s high‐speed runs, would lead to improved performance as well as increased maximum oxygen uptake (VO2‐max) and muscle oxidative phosphorylation (OXPHOS). In addition, to examine to what extent the effects would compare to 10‐20‐30 running conducted with maximal effort. Design: Nineteen males were randomly assigned to 10‐20‐30 running performed with either submaximal (SUBMAX; n = 11) or maximal (MAX; n = 8) effort, which was conducted three times/week for 6 weeks (intervention; INT). Before and after INT, subjects completed a 5‐km running test and a VO2‐max test, and a biopsy was obtained from m. vastus lateralis. Results: After compared to before INT, SUBMAX and MAX improved (p < 0.05) 5‐km performance by 3.0% (20.8 ± 0.4 (means±SE) vs. 21.5 ± 0.4 min) and 2.3% (21.2 ± 0.4 vs. 21.6 ± 0.4 min), respectively, and VO2‐max was ~7% higher (p < 0.01) in both SUBMAX (57.0 ± 1.3 vs. 53.5 ± 1.1 mL/min/kg) and MAX (57.8 ± 1.2 vs. 53.7 ± 0.9 mL/min/kg), with no difference in the changes between groups. In SUBMAX, muscle OXPHOS was unchanged, whereas in MAX, muscle OXPHOS subunits (I‐IV) and total OXPHOS (5.5 ± 0.3 vs 4.7 ± 0.3 A.U.) were 9%–29% higher (p < 0.05) after compared to before INT. Conclusion: Conducting 10‐20‐30 training with a non‐maximal effort during the 10‐s high‐speed runs is as efficient in improving 5‐km performance and VO2‐max as maximal effort exercise, whereas increase in muscle OXPHOS occur only when the 10‐s high‐speed runs are performed with maximal effort. [ABSTRACT FROM AUTHOR]

Background: There has been an increase in the number of studies examining the effect of acute and chronic physical activity on academic outcomes in children and adolescents in the last two decades. We aimed to systematically determine the acute effects of physical activity on academic outcomes in school‐aged youth and to examine possible moderators. Methods: We conducted a systematic search using PubMed, Web of Science, SPORTDiscus, and PsycINFO databases (from inception to 11th January 2023) for studies assessing the acute effects of physical activity on academic performance‐related outcomes in school‐aged youth. A univariate and multivariate meta‐analysis was conducted based on a random‐effects model with restricted maximum likelihood used to pool the academic outcomes results (Hedge's g). Results: We included 11 articles (803 children and adolescents [range: 6–16 years]) in the systematic review. Overall, acute physical activity increased academic outcomes (Hedge's g = 0.35, 95% CI: 0.20–0.50). Multivariate meta‐analyses revealed that physical activity increased academic performance in mathematics (Hedge's g = 0.29, 95% CI: 0.16–0.42) and language (Hedge's g = 0.28, 95% CI: 0.09–0.47). Only behavior change techniques (Hedge's g = 0.54, 95% CI, 0.18–0.90, p < 0.001) played a significant role in this relationship. Conclusions: A single bout of physical activity can improve academic outcomes in school‐aged youth, which may serve as a complementary tool for the educational field. However, the observed heterogeneity in the results indicates that we should interpret the findings obtained with caution. [ABSTRACT FROM AUTHOR]

Torsion of the Achilles tendon (AT) enhances tensile strength, but a high degree of torsion might also be a risk factor for Achilles tendinopathy, due to greater internal compression exerted during tensile loading. However, evidence supporting the grounds for this assumption is lacking. Hence, we aimed to investigate the impact of AT torsion type on intratendinous pressure. Eighteen human fresh frozen cadaveric legs were mounted in a testing rig and a miniature pressure catheter was placed through ultrasound‐guided insertion in the midportion region of the AT. Intratendinous pressure was measured during a simulated straight‐knee calf stretch and eccentric heel drop. The AT was then carefully dissected and classified into Type I (least), Type II (moderate), and Type III (extreme) torsion. Of the ATs examined, nine were found to have Type I torsion (50%), nine Type II (50%), and none Type III. It was found that the intratendinous pressure of the AT increased exponentially with ankle dorsiflexion during both exercises (p < 0.001) and that this increase was greater in ATs with Type II torsion than Type I torsion (p < 0.05). This study provides the first biomechanical data to support the hypothesis that in athletes with a high degree of torsion in the AT, the midportion area will experience more internal compression during exercise, for example, calf stretching and eccentric heel drops. Whether this phenomenon is also associated with an elevated risk for Achilles tendinopathy needs further prospective investigation. [ABSTRACT FROM AUTHOR]

The purpose of the study was to compare the degree of intersubject variability in the cardiorespiratory, metabolic, and perceptual responses to high‐intensity interval training (HIIT) prescribed based on the relative anaerobic speed reserve (ASR) or maximal aerobic speed (MAS) and to identify the optimal % ASR for execution of such HIIT. Seventeen male physical education students (age: 23.6 ± 1.1 years, height: 180.2 ± 5.9, body mass: 78.3 ± 8.1 kg; % body fat: 14.3 ± 2.7%) volunteered to execute three randomly scheduled 10‐min HIIT exercises at 110% vVO2max, Δ15% ASR, or Δ25% ASR. Analysis of variance for repeated measures and the least significant difference post‐hoc test were used to compare the physiological responses and the mean of individual residuals between the training sessions. The coefficients of variation (CV) of time spent ≥90% of maximal oxygen uptake (VO2max) and maximal heart rate (HRmax), peak VO2, mean VO2, peak HR, mean HR, blood lactate [La], and rating of perceived exertion (RPE) were 48.7%, 35.9%, 9.3%, 7%, 3.5%, 4.8%, 32%, and 16.9% during 110% vVO2max, 47.2%, 31%, 7.5%, 6.7%, 3.9%, 4.6%, 24.2%, and 14.6% during Δ15% ASR, and 48.1%, 31.5%, 7.6%, 8.4%, 3.6%, 4.1%, 20.2%, and 3.4% during Δ25% ASR session, respectively. Only the residuals in RPE were significantly (p < 0.001) higher in 110% vVO2max and Δ15% ASR in comparison to Δ25% ASR. Time spent ≥90% HRmax/VO2max was maximized during Δ15% ASR session, albeit this was not significantly different from other sessions. The ASR‐based method leads to reduced CVs of physiological and perceptual responses during 10‐min HIIT; however, only reductions in [La] and RPE may be considered practically meaningful. Practitioners can use vVO2max for prescription of 10‐min HIIT session comprised of 15‐s work and passive recovery intervals. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of full marathon running on intrinsic and extrinsic foot muscle damage and to determine the relationship with the height change of the longitudinal foot arch following full marathon completion. Methods: Magnetic resonance imaging‐measured transverse relaxation time (T2) of the abductor hallucis (ABH), flexor digitorum brevis (FDB) and quadratus plantae (QP), flexor digitorum longus (FDL), tibialis posterior (TP), and flexor hallucis longus (FHL) from 22 collegiate runners were assessed before and 1, 3, and 8 days after full marathon running. The three‐dimensional foot posture of 10 of the 22 runners was further obtained using a foot scanner system before and 1, 3, and 8 days after the marathon. Results: Marathon‐induced increases in T2 were observed in the QP, FDL, TP, and FHL 1 day after the marathon (+7.5%, +4.7%, +6.7%, and +5.9%, respectively), with the increased T2 of TP persisting until 3 days after the marathon (+4.6%). T2 changes of FDL and FHL from pre‐marathon to DAY 1 showed direct correlations with the corresponding change in the arch height ratio (r = 0.823, p = 0.003, and r = 0.658, p = 0.038). Conclusion: The damage and recovery response from a full marathon differed among muscles; QP, FDL, TP, and FHL increased T2 after the marathon, whereas ABH and FDB did not. In addition, T2 changes in FDL and FHL and the arch height ratio change were correlated. Our results suggest that the extrinsic foot muscles could be more susceptible to damage than the intrinsic during marathon running. [ABSTRACT FROM AUTHOR]

Purpose: To investigate whether 4 weeks of normobaric "live high–train low and high" (LHTLH) causes different hematological, cardiorespiratory, and sea‐level performance changes compared to living and training in normoxia during a preparation season. Methods: Nineteen (13 women, 6 men) cross‐country skiers competing at the national or international level completed a 28‐day period (∼18 h day−1) of LHTLH in normobaric hypoxia of ∼2400 m (LHTLH group) including two 1 h low‐intensity training sessions per week in normobaric hypoxia of 2500 m while continuing their normal training program in normoxia. Hemoglobin mass (Hbmass) was assessed using a carbon monoxide rebreathing method. Time to exhaustion (TTE) and maximal oxygen uptake (VO2max) were measured using an incremental treadmill test. Measurements were completed at baseline and within 3 days after LHTLH. The control group skiers (CON) (seven women, eight men) performed the same tests while living and training in normoxia with ∼4 weeks between the tests. Results: Hbmass in LHTLH increased 4.2 ± 1.7% from 772 ± 213 g (11.7 ± 1.4 g kg−1) to 805 ± 226 g (12.5 ± 1.6 g kg−1) (p < 0.001) while it was unchanged in CON (p = 0.21). TTE improved during the study regardless of the group (3.3 ± 3.4% in LHTLH; 4.3 ± 4.8% in CON, p < 0.001). VO2max did not increase in LHTLH (61.2 ± 8.7 mL kg−1 min−1 vs. 62.1 ± 7.6 mL kg−1 min−1, p = 0.36) while a significant increase was detected in CON (61.3 ± 8.0–64.0 ± 8.1 mL kg−1 min−1, p < 0.001). Conclusions: Four‐week normobaric LHTLH was beneficial for increasing Hbmass but did not support the short‐term development of maximal endurance performance and VO2max when compared to the athletes who lived and trained in normoxia. [ABSTRACT FROM AUTHOR]

Acute bouts of physical exercise have the potential to benefit children's cognition. Inconsistent evidence calls for systematic investigations of dose–response relations between quantitative (intensity and duration) and qualitative (modality) exercise characteristics. Thus, in this study the optimal duration of an acute cognitively challenging physical exercise to benefit children's cognition was investigated, also exploring the moderating role of individual characteristics. In a within‐subject experimental design, 104 children (Mage = 11.5, SD = 0.8, 51% female) participated weekly in one of four exergaming conditions of different durations (5, 10, 15, 20 min) followed by an Attention Network task (ANT‐R). Exergame sessions were designed to keep physical intensity constant (65% HRmax) and to have a high cognitive challenge level (adapted to the individual ongoing performance). Repeated measures ANOVAs revealed a significant effect of exercise duration on reaction times (RTs; p = 0.009, ƞ2p = 0.11), but not on response accuracy. Post hoc analyses showed faster information processing speed after 15 min of exercise compared to 10 min (p = 0.019, ƞ2p = 0.09). Executive control, alerting and orienting performances and interactions were unaffected by exercise duration (ps > 0.05). Among individual characteristics, habitual physical activity moderated duration effects on RTs. For more active children, exercise duration influenced the interaction between executive control and orienting (p = 0.034; ƞ2p = 0.17) with best performances after the 15 min duration. Results suggest that an acute 15 min cognitively high‐challenging bout of physical exercise enhances allocable resources, which in turn facilitate information processing, and—for more active children only—also executive processes. Results are interpreted according to the arousal theory and cognitive stimulation hypothesis. [ABSTRACT FROM AUTHOR]

Aim: The aim of the present study was to compare performance 5 h after a 90‐min endurance training session when either carbohydrate only or carbohydrate with added whey hydrolysate or whey isolate was ingested during the first 2 h of the recovery period. Methods: Thirteen highly trained competitive male cyclists completed three exercise and diet interventions (double‐blinded, randomized, crossover design) separated by 1 week. The 90‐min morning session (EX1) included a 60 min time‐trial (TT60). Immediately and 1 h after exercise, participants ingested either (1) 1.2 g carbohydrate∙kg−1∙h−1 (CHO), (2) 0.8 g carbohydrate∙kg−1∙h−1 + 0.4 g isolate whey protein∙kg−1∙h−1 (ISO) or (3) 0.8 g carbohydrate∙kg−1∙h−1 + 0.4 g hydrolysate whey protein∙kg−1∙h−1 (HYD). Additional intakes were identical between interventions. After 5 h of recovery, participants completed a time‐trial performance (TTP) during which a specific amount of work was performed. Blood and urine were collected throughout the day. Results: TTP did not differ significantly between dietary interventions (CHO: 43:54 ± 1:36, ISO: 46:55 ± 2:32, HYD: 44:31 ± 2:01 min). Nitrogen balance during CHO was lower than ISO (p < 0.0001) and HYD (p < 0.0001), with no difference between ISO and HYD (p = 0.317). In recovery, the area under the curve for blood glucose was higher in CHO compared to ISO and HYD. HR, VO2, RER, glucose, and lactate during EX2 were similar between interventions. Conclusion: Performance did not differ after 5 h of recovery whether carbohydrate only or isocaloric carbohydrate plus protein was ingested during the first 2 h. Correspondingly, participants were not in negative nitrogen balance in any dietary intervention. [ABSTRACT FROM AUTHOR]

Rationale: More research is needed to uncover the effectiveness of combined strength and foam‐rolling interventions to prevent running‐related injuries. Objectives: To evaluate effectiveness of an 18‐week general strength and foam‐rolling intervention on the incidence of running‐related injuries. Method: This is an 18‐week observational comparative study. A total of 433 recreational runners participated (n = 203 female). The intervention group (n = 228) performed general strength and foam‐rolling exercises twice weekly for 18 weeks, the control group (n = 205) maintained their regular training habits. Running volume and running‐related pain were reported weekly. Secondary analyses were performed on the subgroups of the intervention group based on compliance; low compliance (n = 100), intermediate compliance (n = 63), and high compliance (n = 65). Cumulative incidence proportions were calculated and time‐to‐event statistics were performed to compare survival times between groups. Univariate cox proportional hazards ratio was calculated to estimate the risk of running‐related injuries at 18 weeks. Results: A total of 100 running‐related injuries were sustained. The cumulative incidence proportion for the control and intervention groups was 27.1% (95% CI: 21.4–33.9) and 23.0% (95% CI: 17.8–29.4), respectively. No statistically significant difference was found between the overall intervention group and control group (log‐rank p = 0.31). A significant difference existed between the high‐compliance subgroup and the control group (log‐rank p = 0.00). Highly compliant runners were 85% less likely (hazard rate ratio = 0.15; 95% CI: 0.05–0.46) to sustain an injury during the study compared with controls. Conclusion: Recreational runners highly compliant with the intervention were 85% less likely and took on average 57 days longer to sustain a running‐related injury when compared with controls, with a cumulative incidence proportion of 4.6% after 18 weeks. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated the mediating role of resilience in the association between moderate‐to‐vigorous physical activity (MVPA) and psychological ill‐being, as well as the moderating role of age in the direct and indirect relationship between MVPA and psychological ill‐being in children with attention‐deficit/hyperactivity disorder (ADHD). Methods: Eighty‐five children aged 6–12 years (Mage = 8.41 ± 1.44 years) diagnosed with ADHD were recruited. Participants wore an accelerometer on their non‐dominant wrist for seven consecutive days to record MVPA. Resilience and psychological ill‐being were assessed using self‐reported questionnaires. Results: MVPA was positively associated with resilience but negatively related to depression and stress. Resilience was negatively correlated with depression and stress. Using the bootstrapping method, the indirect effect of resilience was found between MVPA and depression (−0.006%, 95% confidence interval [CI] = [−0.060, −0.020]) in children with ADHD, supporting partial mediation. Moderated mediation analysis further demonstrated that the indirect effect of MVPA on depression via resilience was stronger in older children (−0.008, 95% CI = [−0.023, −0.001]) than in younger children with ADHD. Conclusion: The findings may inform future empirical studies on designing exercise interventions with MVPA levels that help to improve resilience and depression in children with ADHD. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate how rifle carriage and skiing speed during biathlon roller skiing affect range of motion (ROM) in joint angles and equipment (skis and poles), the vertical distance between shoulders and treadmill (vertdist), as well as possible sex differences associated with rifle carriage. Methods: Fourteen biathletes (6 women, 8 men) roller‐skied on a treadmill at submaximal and simulated race speeds, with (WR) and without (NR) a rifle, using gears 3 and 2. Kinematical data for the whole body, poles, roller‐skis, rifle, and treadmill were monitored using a 3D motion capture system. Movements determined as flexion/extension (x), abduction/adduction (y), and/or internal/external rotation (z) were analyzed for the hip, shoulder, thorax, knee, ankle, elbow, poles, and roller skis. ROM (the difference between maximal and minimal angles) in joints and equipment, and vertdist were analyzed over six skiing cycles during each condition (WR and NR) and speed. Results: The maximal vertdist was lower for WR compared with NR (gear 3: 1.53 ± 0.06 vs 1.54 ± 0.06 m; gear 2: 1.49 ± 0.06 vs 1.51 ± 0.06 m; both p < 0.001). ROM in the upper body was altered when roller skiing WR (movements decreased in thorax and shoulder (x) and increased in elbow (only gear 3) (x), thorax (only gear 2), and shoulder (y) and (z); all p < 0.05) and increased with speed, without differences between sexes (p > 0.05). Conclusion: Since rifle carriage and speed appear to affect the kinematics of roller skiing, coaches, and biathletes are advised to perform skiing technique training under competition‐like conditions (i.e., at race speeds while carrying the rifle). [ABSTRACT FROM AUTHOR]

The Doha agreement classification is used to classify groin pain in athletes. We evaluated the inter‐examiner reliability of this classification system. We prospectively recruited 48 male athletes (66 symptomatic sides) with groin pain between 10–2017 and 03–2020 at a sports medicine hospital in Qatar. Two examiners (23 and 10 years of clinical experience) performed history taking, and a standardized clinical examination blinded to each other's findings. Examiners classified groin pain using the Doha agreement terminology (adductor‐, inguinal‐, iliopsoas‐, pubic‐, hip‐related groin pain, or other causes of groin pain). Multiple entities were ranked in order of perceived clinical importance. Each side was classified separately for bilateral groin pain. Inter‐examiner reliability was calculated using Cohen's Kappa statistic (κ). Inter‐examiner reliability was slight to moderate for adductor‐ (κ = 0.40), inguinal‐ (κ = 0.44), iliopsoas‐ (κ = 0.57), and pubic‐related groin pain (κ = 0.12), substantial for hip‐related groin pain (κ = 0.62), and slight for "other causes of groin pain" (κ = 0.13). Ranking entities in order of perceived clinical importance improved inter‐examiner reliability for adductor‐, inguinal‐, and iliopsoas‐related groin pain (κ = 0.52–0.65), but not for pubic (κ = 0.12), hip (κ = 0.51), and "other causes of groin pain" (κ = 0.03). For participants with unilateral groin pain classified with a single entity (n = 7), there was 100% agreement between the two examiners. Inter‐examiner reliability of the Doha agreement meeting classification system varied from slight to substantial, depending on the clinical entity. Agreement between examiners was perfect when athletes were classified with a single clinical entity of groin pain, but lower when athletes were classified with multiple clinical entities. [ABSTRACT FROM AUTHOR]

Grounded in hedonic assumptions, evidence suggests that people tend to engage in activities they consider pleasurable and enjoyable, while trying to avoid pain and displeasure. This suggests that the dynamic between positive and negative affect can influence current behavior and the intentions to continue performing. Regarding resistance training (RT), research focusing on how to promote a better affective response is still scarce and much needed. Given existing limitations and theoretical suggestions, a RT program was developed and applied to recreational exercisers in a quasi‐experimental design aiming to (1) explore the affective response dynamic through an assessment after the last set of each exercise; and (2) analyze possible differences of preference and tolerance profiles in affective variables (core affect and enjoyment). For that purpose, 43 participants (21 male and 22 female; Mage = 34.69 ± 6.71 years; Mexperience = 8.32 ± 4.54 years; MBMI = 24.26 ± 2.64 kg/m2) accepted to participate in this study. Descriptive statistics, correlational, and group comparisons analyses were performed to provide evidence for proposed objectives. The present study showed that measures of affective valence/arousal applied immediately after a set represents a feasible and ecologically valid approach to tap core affect. Results presented evidence that recreationally trained exercisers in a common RT program would need a minimum of one measurement to assess the affective response. However, additional assessments could refine the understanding of exercise pleasurable experience. Results also suggest that exercisers with distinct profiles of preference/tolerance depicted differentiated patterns for the affective response, possibly justifying a distinct approach when promoting affective regulation. [ABSTRACT FROM AUTHOR]

While it is well recognized that the preferred stride frequency (PSF) in running closely corresponds to the metabolically optimal frequency, the underlying mechanisms are still unclear. Changes in joint kinematics when altering stride frequency will affect the muscle‐tendon unit lengths and potentially the efficiency of muscles crossing these joints. Here, we investigated how fascicle kinematics and forces of the triceps surae muscle, a highly energy consuming muscle, are affected when running at different stride frequencies. Twelve runners ran on a force measuring treadmill, adopting five different frequencies (PSF; PSF ± 8%; PSF ± 15%), while we measured joint kinematics, whole‐body energy expenditure, triceps surae muscle activity, and soleus (SOL; N = 10) and gastrocnemius medialis (GM; N = 12) fascicle kinematics. In addition, we used dynamic optimization to estimate SOL and GM muscle forces. We found that SOL and GM mean muscle fascicle length during stance followed an inverted U‐relationship with the longest fascicle lengths occurring at PSF. Fascicle lengths were shortest at frequencies lower than PSF. In addition, average SOL force was greater at PSF−15% compared with PSF. Overall, our results suggest that reduced SOL and GM muscle fascicle lengths, associated with reduced muscle force potential, together with greater SOL force demand, contribute to the increased whole‐body energy expenditure when running at lower than PSF. At higher stride frequencies, triceps surae muscle kinematics and force production were less affected suggesting that increased energy expenditure is rather related to higher cost of leg swing and greater cost of force production. [ABSTRACT FROM AUTHOR]

Frontal plane postures during the ultimate step of sidestepping are linked to increased anterior cruciate ligament injury risk. However, there is a lack of research detailing the kinematic strategies present in the penultimate step. This study, therefore, investigated penultimate and ultimate step kinematics of planned sidestepping (pSS) and unplanned sidestepping (upSS) to further understand the effect of planning time on known ultimate step kinematic and kinetic differences. Sixty male amateur Australian Rules football players performed three trials of straight‐line running (RUN), pSS, and upSS in a randomized order. Mediolateral foot placement and three‐dimensional joint kinematics for the knee, pelvis, and trunk were measured at final foot contact of the penultimate step and initial foot contact of the ultimate step. Peak knee moments were measured during the weight acceptance phase of the ultimate step. In pSS, at the penultimate step final foot contact, the support foot was placed across the midline of the center of mass, in the frontal plane, contralateral to the sidestep direction. Greater trunk lateral flexion toward the sidestep direction and greater negative pelvic lateral tilt were observed in pSS compared with upSS and RUN. Differences between pSS and upSS frontal plane kinematics at penultimate step final foot contact suggest preparatory reorientation strategies are likely constrained by the amount of planning time available. As there are clear differences in preparatory kinematics, we recommend that planning time be considered when training and assessing sidestepping maneuvers and planned and unplanned maneuvers not be treated as interchangeable skills. [ABSTRACT FROM AUTHOR]

Acute increases in tendon blood flow and oxygenation after stress (i.e., hyperemic response) can enhance tendon recovery. While loading intensity is a fundamental part of resistance training programs, its effects on tendon's hyperemic response are unknown. This study aimed to compare acute changes in total (total hemoglobin [THb]) and oxygenated hemoglobin (HbO2) concentrations in the patellar tendon after isometric exercise at different intensities. Thirteen participants performed 8 (5 s) isometric knee extensions at 25%, 50%, and 75% maximal load (maximal voluntarily isometric contraction [MVIC]), separated by 20 min recovery, prescribed in randomized and counterbalanced order. Changes in patellar tendon THb, HbO2 and deoxygenated hemoglobin (HHb) in response to exercise at each intensity were measured using near‐infrared spectroscopy. Post‐exercise, HbO2 increased with 50% (ηp2 = 0.305, f = 5.26, p < 0.01) and 75% (ηp2 = 0.245, f = 4.56, p < 0.01) but not 25% (ηp2 = 0.088, f = 1.16, p = 0.339) MVIC, while THb increased in 50% (ηp2 = 0.305, f = 5.26, p = 0.01) but not 25% (ηp2 = 0.067, f = 0.865, p = 0.51) or 75% (ηp2 = 0.126, f = 1.729, p = 0.14) MVIC. Additionally, increasing load from 25% to 50% MVIC resulted in greater THb (f = 2.459, p = 0.43), HbO2 (f = 3.389, p = 0.13) and HHb (f = 0.320, p = 0.01) post‐exercise responses, but no differences were observed between 50% and 75% MVIC (THb: f = 0.748, p = 0.59; HbO2: f = 0.825, p = 0.54; HHb: f = 0.713, p = 0.62). Our results suggest there is a loading threshold at ~50% MVIC at which the tendon hyperemic response is fully achieved. Training above this intensity is not expected to provide any additional change to the tendon microvascular response. Therefore, moderate loading seems to be sufficient to fully elicit the patellar tendon hyperemic response that's believed to stimulate tendon healing. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the effects of three different unilateral isoinertial resistance training protocols with eccentric overload on changes in lean mass and muscle function of trained (TL) and contralateral non-trained (NTL) legs. Methods: Physically active university students were randomly assigned to one of three training groups or a control group (n = 10/group). Participants in the training groups performed dominant leg isoinertial squat training twice a week for 6 weeks (4 sets of 7 repetitions) using either an electric-motor device with an eccentric phase velocity of 100% (EM100) or 150% (EM150) of concentric phase velocity or a conventional flywheel device (FW) with the same relative inertial load. Changes in thigh lean mass, unilateral leg-press one-repetition maximum (1-RM), muscle power at 40–80% 1-RM, and unilateral vertical jump height before and after training were compared between the groups and between TL and NTL. Results: No changes in any variable were found for the control group. In TL, all training groups showed similar increases (p < 0.05) in 1-RM strength (22.4–30.2%), lean tissue mass (2.5–5.8%), muscle power (8.8–21.7%), and vertical jump height (9.1–32.9%). In NTL, 1-RM strength increased 22.0–27.8% without significant differences between groups; however, increases in lean mass (p < 0.001) were observed for EM150 (3.5%) and FW (3.8%) only. Unilateral vertical jump height (6.0–32.9%) and muscle power (6.8–17.5%) also increased in NTL without significant differences between training groups. Conclusion: The three eccentric-overload resistance training modalities produced similar neuromuscular changes in both the trained and non-trained legs, suggesting that strong cross-education effects were induced by the eccentric-overload training. [ABSTRACT FROM AUTHOR]

Individuals with chronic ankle instability (CAI) are believed to rely more on visual information during postural control due to impaired proprioceptive function, which may increase the risk of injury when their vision is limited during sports activities. Objectives: To compare (1) the effects of balance training with and without stroboscopic glasses on postural control and (2) the effects of the training on visual reliance in patients with CAI. Design: A randomized controlled clinical trial. Methods: Twenty‐eight CAI patients were equally assigned to one of 2 groups: strobe or control group. The strobe group wore stroboscopic glasses during a 4‐week balance training. Static postural control, a single‐leg hop balance test calculated by Dynamic Postural Stability Index (DPSI), and the Y‐Balance test (YBT) were measured. During the tests, there were different visual conditions: eyes‐open (EO), eyes‐closed (EC), and strobe vision (SV). Romberg ratios were then calculated as SV/EO, and EC/EO and used for statistical analysis. Results: The strobe group showed a higher pretest‐posttest difference in velocity in the medial‐lateral direction and vertical stability index under SV compared with the control group (p <.05). The strobe group showed higher differences in EC/EO for velocity in the medial‐lateral and anterior‐posterior directions, and 95% confidence ellipse area (p <.05), and in SV/EO for velocity in the medial‐lateral, 95% confidence ellipse area, and YBT‐anterior direction (p <.05). Conclusion: The 4‐week balance training with stroboscopic glasses appeared to be effective in improving postural control and altering visual reliance in patients with CAI. [ABSTRACT FROM AUTHOR]

Beneficial acute effects of resistance exercise on cognitive functions may be modified by exercise intensity or by habitual physical activity. Twenty‐six participants (9 female and 17 male; 25.5 ± 3.4 years) completed four resistance exercise interventions in a randomized order on separate days (≥48 h washout). The intensities were set at 60%, 75%, and 90% of the one repetition maximum (1RM). Three interventions had matched workloads (equal resistance*nrepetitions). One intervention applied 75% of the 1RM and a 50% reduced workload (resistance*nrepetitions = 50%). Cognitive attention (Trail Making Test A—TMTA), task switching (Trail Making Test B—TMTB), and working memory (Digit Reading Spans Backward) were assessed before and immediately after exercise. Habitual activity was assessed as MET hours per week using the International Physical Activity Questionnaire. TMTB time to completion was significantly shorter after exercise with an intensity of 60% 1RM and 75% 1RM and 100% workload. Friedman test indicated a significant effect of exercise intensity in favor of 60% 1RM. TMTA performance was significantly shorter after exercise with an intensity of 60% 1RM, 90% 1RM, and 75% 1RM (50% workload). Habitual activity with vigorous intensity correlated positively with the baseline TMTB and Digit Span Forward performance but not with pre‐ to post‐intervention changes. Task switching, based on working memory, mental flexibility, and inhibition, was beneficially influenced by acute exercise with moderate intensity whereas attention performance was increased after exercise with moderate and vigorous intensity. The effect of regular activity had no impact on acute exercise effects. [ABSTRACT FROM AUTHOR]

This study aimed to compare neuromuscular alterations and perceptions of effort and muscle pain induced by concentric and eccentric cycling performed at the same power output or effort perception. Fifteen participants completed three 30‐min sessions: one in concentric at 60% peak power output (CON) and two in eccentric, at the same power output (ECCPOWER) or same perceived effort (ECCEFFORT). Muscle pain, perception of effort, oxygen uptake as well as rectus femoris and vastus lateralis electromyographic activities were collected when pedaling. The knee extensors maximal voluntary contraction (MVC) torque, the torque evoked by double stimulations at 100 Hz and 10 Hz (Dt100; Dt10), and the voluntary activation level (VAL) were evaluated before and after exercise. Power output was higher in ECCEFFORT than CON (89.1 ± 23.3% peak power). Muscle pain and effort perception were greater in CON than ECCPOWER (p < 0.03) while muscle pain was similar in CON and ECCEFFORT (p > 0.43). MVC torque, Dt100, and VAL dropped in all conditions (p < 0.04). MVC torque (p < 0.001) and the Dt10/ Dt100 ratio declined further in ECCEFFORT (p < 0.001). Eccentric cycling perceived as difficult as concentric cycling caused similar muscle pain but more MVC torque decrease. A given power output induced lower perceptions of pain and effort in eccentric than in concentric yet similar MVC torque decline. While neural impairments were similar in all conditions, eccentric cycling seemed to alter excitation‐contraction coupling. Clinicians should thus be cautious when setting eccentric cycling intensity based on effort perception. [ABSTRACT FROM AUTHOR]

The article discusses research on the effects of the COVID-19 pandemic on the performance of professional tennis players based on their match statistics using a large-scale population-based approach. Research data shows the percentages of service games won, total points won, first and second service points won, service aces and breakpoints faced. The study identified training strategies for improving service performance hat have less pandemic-related restrictions.

Resistance exercises eliciting eccentric overload (EO) are considered to strongly promote muscular hypertrophy and broad neuromuscular adaptations but typically require specialized equipment. The aims of these experiments were to assess whether EO is achieved during common high‐speed stretch‐shortening cycle (SSC) exercises (rebound bench press throw [RBPT] and squat jump [SJ]), and to test the effect of the external load on the EO achieved. Twenty‐nine under 18 handball players and fifteen physically active males (24.9 ± 3.2 years) took part in the experiments. Testing consisted of a single set of 6 repetitions with light (25%–30% 1‐RM), moderate (50% 1‐RM), and heavy (70%–75% 1‐RM) loads. Eccentric and concentric force near the zero‐velocity point (50–200 ms) as well as eccentric‐concentric force ratio (EO; %) were calculated. In RBPT, higher EO values were found at 50% 1‐RM than 70% 1‐RM in the time interval 50 ms before and after the zero‐velocity point. Higher EO values were also found at 50% 1‐RM than both 30% 1‐RM and 70% 1‐RM 100 ms before and after the zero‐velocity point. For the SJ, higher EO values were found at 50% 1‐RM and 75% 1‐RM than 25% 1‐RM 100 ms before and after the zero‐velocity point. Higher EO values were found at 50% 1‐RM than 25% 1‐RM 200 ms before and after the zero‐velocity point. However, the higher EO values in the SJ were found far from the zero‐velocity point. High‐speed SSC resistance training provides similar EO to other methods and thus should promote muscle hypertrophy and other neuromuscular adaptations. [ABSTRACT FROM AUTHOR]

Investigating physical activity (PA) patterns as a detailed intensity spectrum instead of crude intensity categories have improved the ability to analyze the relationship between measured PA and health variables. The aim of this methodological study was to introduce and investigate the utility of using detailed PA intensity spectrum compared to crude PA intensity categories for comparison of PA between groups and between repeated measures. The study sample consisted of two groups of children, where one group was scheduled for extended physical education (PE) by daily classes while the other group followed usual PE schedule. Accelerometer data was processed into traditional crude PA intensity categories and into detailed PA intensity spectrum. Multivariate partial least squares regression for discriminant analysis (PLS‐DA) was applied for PA intensity spectrum group comparison and compared to traditional univariate statistical analysis. Repeated measures were investigated using independent PLS‐DA as well as multilevel PLS‐DA for paired analysis. While traditional analysis of crude PA intensity categories was unable to find any group differences, multivariate analysis of the PA intensity spectrum identified statistically significant differences. By the extension of multilevel PLS‐DA for paired comparison, a clear difference in the PA intensity spectrum was demonstrated between repeated measures. In conclusion, analysis of detailed PA intensity spectrum demonstrates utility for comparing detailed PA data between groups and between repeated measures in interventional and observational research. [ABSTRACT FROM AUTHOR]

Loading intervention is currently the preferred management of tendinopathy, but to what extent different loading regimes influence the mechanical response in tendons is scarcely investigated. Therefore, the purposes of the investigation were to examine the effect of exercise interventions with either high or low load magnitude applied to the tendinopathic patellar tendon and the influence on its mechanical, material, and morphological properties. Forty‐four men with chronic patellar tendinopathy were randomized to 12 weeks of exercising with either; 55% of 1RM throughout the period (MSR group) or 90% of 1RM (HSR group), and with equal total exercise volume in both groups. Mechanical (stiffness), material (T2* relaxation time), and morphological (cross‐sectional area (CSA)) properties were assessed at baseline and after 12 weeks of intervention. MRI with ultra‐short echo times (UTE) and T2*‐mapping was applied to explore if T2* relaxation time could be used as a noninvasive marker for internal material alteration and early change thereof in response to intervention. There was no effect of HSR or MSR on the mechanical (stiffness), material (T2* relaxation time) or morphological (CSA) properties, but both regimes resulted in significant strength gain. In conclusion, there were no statistically superior effect of exercising with high (90%) compared to moderate (55%) load magnitude on the mechanical, material or morphological properties. [ABSTRACT FROM AUTHOR]

High‐level patellar tendon strain may cause impairments of the tendon's micromorphological integrity in growing athletes and increase the risk for tendinopathy. This study investigated if an evidence‐based tendon exercise intervention prevents high‐level patellar tendon strain, impairments of micromorphology and pain in adolescent basketball players (male, 13–15 years). At three time points over a season (M1‐3), tendon mechanical properties were measured using ultrasound and dynamometry, proximal tendon micromorphology with a spatial frequency analysis and pain and disability using VISA‐P scores. The control group (CON, n = 19) followed the usual strength training plan, including sprint and change‐of‐direction drills. In the intervention group (INT, n = 14), three sessions per week with functional exercises were integrated into the training, providing repetitive high‐magnitude tendon loading for at least 3 s per repetition. The frequency of high‐level strain (ie, ≥9%) continuously decreased in INT, while tending to increase in CON since tendon force increased in both (p < 0.001), yet tendon stiffness only in INT (p = 0.004). In CON, tendon strain was inversely associated with tendon peak spatial frequency at all time points (p < 0.05), indicating impairments of tendon micromorphological integrity with higher strain, but not at M2 and M3 in INT. Descriptively, the fraction of asymptomatic athletes at baseline was similar in both groups (~70%) and increased to 100% in M3 in INT, while remaining unchanged in CON. We suggest that functional high‐load tendon exercises could reduce the prevalence of high‐level patellar tendon strain and associated impairments of its micromorphology in adolescent athletes, providing new opportunities for tendinopathy prevention. [ABSTRACT FROM AUTHOR]

This study aimed to establish the association and differences in a diversity of cognitive domains according to cardiorespiratory fitness (CRF), muscular fitness (MF), and speed‐agility fitness (S‐AF) level in a large sample of Chilean schoolchildren. 1171 Chilean schoolchildren aged 10–14 years participated. CRF, MF, and S‐AF were assessed through the ALPHA‐fitness test battery. Cognition was evaluated through the NeuroCognitive Performance Test, which involved eight tests related to four main domains: cognitive flexibility (CF), working memory (WM), inhibitory control (IC), and intelligence (IN). Both global (multivariate) and individual (univariate) analyses were performed to determine the differences in cognitive functioning according to low‐, middle‐, and high‐fitness level. The global analyses showed a significant main effect for CRF, F(16,940) = 3.08, p ≤.001 and MF groups, F(16,953) = 2.30, p =.002, but not for S‐AF, F(16,948) = 1.37, p =.105. CRF shows a significant main effect in seven of eight tests, involving CF, WM, IC, and IN domains, whereas MF shows a significant main effect in five of eight tests without association with IN. SA‐F shows a significant main effect only with IC. Statistical differences were found between the low‐ and middle/high‐fitness groups but not between the middle‐ and high‐fitness groups. At a global level, both CRF and MF seem to be associated with a higher cognitive profile in scholars; however, at an individual level, all fitness components show a favorable relationship to some cognitive domine. Then, future cognitive developing strategies should consider all fitness components, prioritizing those low‐fitness schoolchildren. [ABSTRACT FROM AUTHOR]

The aim was to provide an overview of the different statistical methods for validation of patient‐reported outcome measures, ranging from simple statistical methods available in all software packages to advanced statistical models that require specialized software. A non‐technical summary of classical test theory (CTT) and modern test theory (MTT) is provided. Specifically, confirmatory factor analysis, item response theory, and Rasch analysis is outlined. One CTT and three MTT methods were used to validate the two subscales (Symptoms and Quality of Life) from the Knee Injury and Osteoarthritis Outcome Score (KOOS). For each methodology, two analyses were considered: (i) a unidimensional analysis ignoring the pre‐specified dimensionality, and (ii) a two‐dimensional analysis using the pre‐specified dimensionality. While CTT did not adequately address central issues regarding the validity of the KOOS subscales, the three MTT methods yielded very similar results. In conclusion, MTT methods offer analysis of all relevant properties related to the validity of patient‐reported outcome measures, while this is not the case for CTT. Claims about sufficient validity based on CTT methods are inadequate and should not be trusted. [ABSTRACT FROM AUTHOR]

Perceived motor competence (PMC) is important to health as it mediates the association between actual motor competence (AMC) and physical activity. Many instruments assess the broader construct of physical self‐perception but no scale has been developed to assess PMC in stability. The aim of this study was to develop and analyze the reliability and validity of a new pictorial PMC in stability skill assessment when completed by early adolescents. A Delphi method showed ≥70% of experts' consensus in the seven proposed items. A sample of 904 students (11‐14 years old) self‐reported PMC in locomotion, object control, and stability using two pictorial scales: Perceived Movement Skill Competence (PMSC) and the newly developed Stability (PMSC_Stability). The Körperkoordinations test for Kinder (KTK) was also administered as a measure of AMC in skills that utilize stability. Two different subsamples were randomly assigned to criterion validity and reliability assessments. Spearman's correlation, confirmatory factor analysis, and a general linear model for sex and age were conducted. The internal consistency (α) and test‐retest (intraclass correlation coefficient) reliability values were good (>0.70). A single‐factor latent model represented stability and did not differ by sex. Stability perception was associated with AMC (rho = 0.51). Stability is important to the performance of many movement skills (eg, single‐leg balance or moving on a narrow surface). Understanding which adolescents have poor stability perception could highlight stability as an area that needs targeting in order to increase physical activity and sport participation. [ABSTRACT FROM AUTHOR]

The purpose was to examine the correlation and association between a single‐item question of self‐rated physical fitness and objective measures of fitness and cardiometabolic risk factors in a large population‐based study. Participants were 3441 men and women aged 18‐85 years who filled in a questionnaire and participated in a clinical health examination in the Danish Health Examination Survey 2007‐2008. Cardiorespiratory fitness was estimated by an indirect maximal exercise test. Muscle strength was measured by (a) sit‐to‐stand test, (b) handgrip strength, and (c) bent arm strength. Body mass index and fat percentage were used as measures for body composition. Associations were derived from regression analyses, correlations were calculated using Spearman's correlation test, and agreement was tested by kappa statistics. Within categories of self‐rated physical fitness moving from lowest to highest, objectively measured cardiorespiratory fitness increased. Self‐rated physical fitness was strongly correlated to cardiorespiratory fitness (rmen = 0.69 and rwomen = 0.65) and moderately correlated to the sit‐to‐stand test (rmen = 0.49 and rwomen = 0.48), bent arm strength (r = 0.45) and fat percentage (r = 0.46) among men, and handgrip strength among women (r =0.41). Mutually adjusted analysis showed a significant association between self‐reported physical fitness and cardiorespiratory fitness for men and women and bent arm strength for women. The single‐item question of physical fitness was correlated to cardiorespiratory fitness, muscle strength, and body composition. However, this study suggests that it mainly captures cardiorespiratory fitness. At the population level, the single‐item question could be a useful tool to identify and monitor variation in fitness levels. [ABSTRACT FROM AUTHOR]

Self‐reported physical activity differs from activity levels measured by device. We tested the effect of a video that visualizes the intensity levels of physical activity to increase the agreement between self‐reported and accelerometer‐based moderate‐to‐vigorous physical activity (MVPA) within a single‐blinded, randomized study. Participants (N = 378, 40‐75 years) wore an accelerometer for seven days. Prior to the collection of self‐reported data by the IPAQ‐SF, participants were randomly assigned (1:1) to a control group (CG) or a video group (VG). The outcome was the absolute difference between self‐reported and accelerometer‐based time spent in MVPA (Δ MVPAIPAQ−Accelerometry). To examine the agreement, we used Spearman correlation coefficients and Bland‐Altman analysis. To test the video effect, we used Wilcoxon signed‐rank test, Bayes factor, and simultaneous‐quantile regression. In total, 302 participants fulfilled the accelerometer wear time criteria (≥10 hours/day; ≥6 days) and completed self‐reports within three days after the wearing period. The median of Δ MVPAIPAQ−Accelerometry was −9.0 min/day (IQR: −32.0 to 66.6) for CG and −11.5 min/day (IQR: −29.9 to 14.3) for VG. Wilcoxon signed‐rank test revealed no differences in Δ MVPAIPAQ−Accelerometry between study groups whereas Bayes factor indicated insensitivity of the data. Simultaneous‐quantile regression revealed no relationship between video presentation and Δ MVPAIPAQ−Accelerometry in the 25th percentile. In the 50th (b = −12.4 [95% CI = −23.2 to −1.5] and 75th percentile (b = −45.7 [95% CI = −70.5 to −20.9]), Δ MVPAIPAQ−Accelerometry was negatively associated with video presentation. To conclude, video‐supported assessment may increase the accuracy of self‐reported MVPA among individuals who slightly underestimated and those who overestimated their MVPA. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the smallest detectable change (SDC), minimally important change (MIC), and factor structure of the Oslo Sports Trauma Research Center (OSTRC) questionnaire severity score in half‐ and full‐marathon runners. Data came from a prospective cohort study, the SUcces Measurement and Monitoring Utrecht Marathon (SUMMUM) 2017 study. Two external anchors, the global rating of change (GRC) and global rating of limitations (GRL), were used to classify the running‐related injuries (RRI) as truly improved, unchanged, or truly worsened. SDC values were calculated at individual and group levels. MIC values were calculated using the visual anchor‐based MIC distribution and mean change methods. Confirmatory factor analysis (CFA) was used to study the a priori hypothesized factor structure. A total of 132 runners who reported the same RRI on two occasions 2 weeks apart were included in the analysis. SDC values at individual and group levels were ≤35.06 and ≤9.30, respectively. With the visual anchor‐based MIC distribution method, the MIC values for RRIs that truly improved according to the GRC and GRL anchors were 13.50 and 18.50, respectively. With the mean change method, the MIC values for RRIs that truly improved according to the GRC and GRL anchors were 15.49 and 45.38, respectively. The CFA confirmed that the OSTRC was a unidimensional questionnaire. The change score of the OSTRC severity score can be used to distinguish between important change and measurement error at a group level using the MIC value 18.50. Because the SDC of the OSTRC severity score was larger than the MIC, it is not advised to use the MIC at an individual level. [ABSTRACT FROM AUTHOR]

Translating patient‐reported outcome measures (PROMs) can alter the meaning of items and undermine the PROM's psychometric properties (quantified as cross‐cultural differential item functioning [DIF]). The aim of this paper was to present the theoretical background for PROM translation, adaptation, and cross‐cultural validation, and assess how PROMs used in sports medicine research have been translated and adapted. We also assessed DIF for the Knee Injury and Osteoarthritis Outcome Score (KOOS) across Danish, Norwegian, and Swedish versions. We conducted a search in PubMed and Scopus to identify the method of translation, adaptation, and validation of PROMs relevant to musculoskeletal research. Additionally, 150 preoperative KOOS questionnaires were obtained from the Scandinavian knee ligament reconstruction registries, and cross‐cultural DIF was evaluated using confirmatory factor analysis and Rasch analysis. There were 392 studies identified, describing the translation of 61 PROMs. Ninety‐four percent were performed with forward‐backward technique. Forty‐nine percent used cognitive interviews to ensure appropriate wording, understandability, and adaptation to the target culture. Only two percent were validated according to modern test theory. No study assessed cross‐cultural DIF. One KOOS subscale showed no cross‐cultural DIF, two had DIF with respect to some (but not all) items, and thus conversion tables could be constructed, and two KOOS subscales could not be pooled. Most PROM translations are of undocumented quality, despite the common conclusion that they are valid and reliable. Scores from three of five KOOS subscales can be pooled across the Danish, Norwegian, and Swedish versions, but two of these must be adjusted for DIF. [ABSTRACT FROM AUTHOR]