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Purpose: This study investigated the test–retest reliability and usefulness of the foot–ankle rebound-jump test (FARJT) for measuring foot–ankle reactive strength metrics in athletes. Methods: Thirty-six highly trained, healthy athletes (5 female; 21.5 [3.9] y; 1.80 [0.10] m; 72.7 [10.4] kg) performed 8 repeated bilateral vertical foot–ankle rebound jumps on 2 testing days. Testing days were 1 week apart, and these sessions were preceded by a familiarization session. Reactive strength metrics were calculated by dividing jump height (in meters) by contact time (in seconds) for the reactive strength index (RSI) and flight time (in seconds) by contact time (in seconds) for the reactive strength ratio (RSR). The mean of 4 jumps (excluding the first and last 2 jumps) on each testing session were considered for RSI and RSR reliability and usefulness analysis. Results: We found a high reliability of the FARJT for RSI (intraclass correlation coefficient [ICC] >.90 and coefficient of variation [CV] = 12%) and RSR (ICC ≥.90 and CV = 8%). Regarding their usefulness, both RSI and RSR were rated as "marginal" in detecting the smallest worthwhile change (typical error > smallest worthwhile change) and "good" in detecting a moderate change in performance. Conclusions: The results showed that a FARJT is a highly reliable test for measuring foot–ankle reactive strength in athletes and useful for quantifying changes, for example, following a training block. However, its usefulness as an accurate daily or weekly monitoring tool in practice is questionable. [ABSTRACT FROM AUTHOR]

Context: The Hip Stability Isometric Test (HipSIT) is commonly employed in clinical settings for evaluating the hip posterolateral muscle strength. In this study, we introduced the "Field Hip Stability Isometric Test" (F-HipSIT) and assessed the intrarater and interrater reliability of this strength assessment specifically designed for sports settings. Design: Reliability study. Methods: Two independent raters (A and B) went to athletes' training facilities to conduct 2 sessions of F-HipSIT spaced at least 1 week apart. The average peak force value from 3 valid attempts of each leg was recorded and normalized by the participant's body mass for statistical analysis. Results: Thirty male and 30 female amateur athletes took part in this study. Rater A obtained similar values in the first (0.39 [0.05] and 0.44 [0.07] kg·f/kg) and second (0.39 [0.06] and 0.45 [0.07] kg·f/kg) testing days for men and women, respectively. Rater B also found similar values in the first (0.35 [0.06] and 0.42 [0.08] kg·f/kg) and second (0.36 [0.06] and 0.45 [0.08] kg·f/kg) testing days for men and women, respectively. Excellent intrarater intraclass correlation coefficient (ICC) values were found for men (ICC =.922) and women (ICC =.930), with coefficient of variation of 6% to 8% and minimal detectable change of 0.06 to 0.10 kg·f/kg. The F-HipSIT presented good interrater reliability for men (ICC =.857) and women (ICC =.868), with coefficient of variation of 5% and minimal detectable change of 0.05 to 0.06 kg·f/kg. Conclusion: The F-HipSIT intrarater and interrater reliability among male and female recreational athletes supports this field test as a quick and convenient screening tool to monitor hip posterolateral muscle strength in sports settings. [ABSTRACT FROM AUTHOR]

Context: The aim of this study was to analyze the muscle activity of the hamstring muscles and the lateral gastrocnemius during different variants of the single-leg bridge (SLB) in futsal players. Design: Cross-sectional study. Methods: Twenty-two futsal players (age = 24.8 [3.9] y) volunteered to participate in this study. The participants performed 3 variations of the SLB with the knee flexed at 45°. The first position was performed with the ankle in plantar position with flat support, the second with the ankle in dorsiflexion (DF) with heel support, and the third with the ankle in DF and external rotation (ER) with heel support. The Wilcoxon rank-sum test assessed the difference between variables for samples with the rank-biserial correlation effect size. Spearman correlation coefficients were used to examine the associations of the percentage maximal voluntary isometric contraction for each muscle with peak force and rate of force development with 3 different variances of the SLB. Results: The variation of ankle DF and ER with heel support generated higher muscle activity in BF in concentric (P<.01, effect size [ES] = -0.613); isometric (P<.042, ES = -0.494); and eccentric (P<.005, ES = -0.668) contraction than ankle DF with heel support. In contrast, the variation of ankle DF and ER with heel support generated fewer muscle activity in lateral gastrocnemius in concentric (P < .001, ES = 0.779); isometric (P < .003, ES = 0.708); and eccentric (P < .014, ES = 0.589) contraction than ankle DF with heel support. Conclusions: The position of DF and ER was the best position in SLB to train the BF. It could be convenient to start rehabilitation of the BF with flat foot postition or ankle in DF with heel support and progress with the position of the ankle in DF and ER with heel support. [ABSTRACT FROM AUTHOR]

Context: Nordic hamstring strength (NH strength) and single leg bridge test (SLBT) scores are used to predict the risk of hamstring strain injury. Although NH strength and SLBT scores may be related, the relationship between NH strength and SLBT score remains unknown. Objectives: This study investigated the relationship between NH strength and SLBT scores in university soccer players. Design: Cross-sectional study. Setting: Research laboratory. Participants: 38 male university soccer players. Main Outcome Measures: NH strength and SLBT scores. Interventions: A participant was instructed to lean forward gradually at the slowest possible speed from a kneeling posture with the knee joint flexed 90° for the NH strength measurement. Participants in the SLBT crossed their arms over their chests, pushed down from their heels, and lifted their hips off the ground as many times as they could until they failed. We investigated the relationship between NH strength and SLBT scores in the left and right sides using Spearman rank correlation coefficient. Additionally, we calculated the percentage of left–right asymmetry in NH strength and SLBT scores and investigated the relationship between these variables using Pearson correlation coefficient. Results: There were no significant correlations between NH strength and SLBT scores in the right (rs =.239, P =.16) and left (rs =.311, P =.065) legs. Furthermore, there was no significant relationship between NH strength and SLBT between-limb asymmetry (r =.073, P =.671). Conclusions: NH strength and SLBT scores could be different indexes, indicating either maximal muscle strength or muscle endurance. Thus, the findings suggested that when assessing risk factors for hamstring strain injury, both NH strength and SLBT scores should be measured. [ABSTRACT FROM AUTHOR]

Purpose: Ice hockey is a team invasion sport characterized by repeated high-intensity skating efforts, technical and tactical skill, physical contact, and collisions requiring considerable levels of muscular strength. The purpose of this study was to evaluate the relationships between lower-body vertical force–time metrics and skating qualities in subelite female ice hockey players. Methods: A cross-sectional cohort design was employed utilizing 14 athletes (body mass = 66.7 [1.8] kg; height = 171.6 [6.2] cm; age = 21.1 [1.7] y). The relationships between metrics of lower-body strength collected from a drop jump, squat jump, countermovement jump, loaded countermovement jump, and an isometric squat and 4 skating qualities collected from a linear sprint, repeated sprint test, and a multistage aerobic test were evaluated. Results: The regression models revealed a positive relationship between relative peak force in the isometric squat and skating multistage aerobic test performance (r2 =.388; P =.017) and a positive relationship between repeated-sprint ability and eccentric mean force during the loaded countermovement jump (r2 =.595; P =.001). No significant relationships were observed between strength metrics and skating acceleration or maximal velocity. Conclusions: These data suggest that skating ability is most affected by relative isometric strength in female ice hockey players. It is recommended that practitioners focus training on tasks that improve relative force output. It is also recommended that isometric relative peak force be used as a monitoring metric for this cohort. [ABSTRACT FROM AUTHOR]

Context: Decreased muscle strength and balance in patients with functional ankle instability (FAI) can be effectively improved by ankle strength training. Low-load blood flow restriction (LL-BFR) training increases muscle size and strength, but there is limited evidence from studies on muscle strength and balance in FAI patients. Objective: To study the effects of LL-BFR training versus high-load training (HLT) on muscle strength and balance in FAI patients. Design: Randomized controlled trial. Participants: Forty-six young adults with a history of FAI. Interventions: Participants in the LL-BFR and HLT groups performed 4 sets (30 x 15 x 15 x 15) of ankle training at 20% to 40% of the one-repetition maximum and 70% to 85% one-repetition maximum, respectively, twice a week for 6 weeks. Main Outcome Measure(s): Plantar flexion, dorsiflexion, inversion, and eversion muscle strength, and the Y-balance test scores were assessed at baseline and after 3 and 6 weeks; the thickness of the tibialis anterior, triceps surae, and peroneus longus muscles were assessed at baseline and after 6 weeks. Results: Inversion, eversion, dorsiflexion, and plantar flexion muscle strength; tibialis anterior, triceps surae, and peroneus longus thickness; and Y-balance test scores were significantly increased in the LL-BFR group after 3 and 6 weeks compared with baseline (P < .05), with no significant difference between the LL-BFR and HLT groups after 6 weeks (P > .05). However, at the end of 3 weeks, eversion muscle strength and Y-balance test scores were significantly higher in the LL-BFR group than in the HLT group (P < .05). Conclusions: Over 6 weeks, LL-BFR training was as effective as HLT in improving ankle muscle strength, muscle thickness, and balance in FAI patients, but LL-BFR training improved the ankle eversion muscle strength and dynamic balance more than HLT did in the early stages of the intervention. This finding will provide a new intervention strategy for the clinical rehabilitation of FAI patients. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects between resisted sled sprint training (RSS) and unresisted sprint training (URS) on sprint and acceleration performance, vertical jump, and maximal strength during an 8-week period of preseason training. Methods: Twenty-six recreational active rugby players were randomly divided into either RSS or URS training groups and then performed 8 weeks of training, 2 sessions/wk of sprint-specific training program. The RSS group performed sprints by towing a sled overloaded with 12.6% of body mass for 2 of the 3 sets of 3 × 20-m sprints, plus one set was carried out with unresisted modality. The URS groups performed 3 sets of 3 × 20-m unresisted sprints. The measures of 10- and 30-m sprint times, vertical jump, and 3-repetition-maximum (3-RM) squat tests were performed at baseline and after 8 weeks. Results: Ten- and 30-m sprint times (P <.05 and η p 2 >.44) improved significantly more in RSS than in URS. Both groups improved significantly in vertical jump and 3-RM squat tests; however, no significant differences (P >.1 and η p 2 <.11) between groups were found. Conclusions: Our findings indicate that an 8-week program of RSS is more effective than URS for enhancing sprint time performance in male recreational active rugby players. In addition, these data suggest that a sled overload corresponding to 12.6% of body mass can induce positive effects on both acceleration and speed performance in recreational active rugby players. [ABSTRACT FROM AUTHOR]

Purpose: To determine the utility of countermovement-jump and Keiser leg-press tests for tracking changes in elite athletes of different sports. Methods: Elite athletes of the Norwegian Olympic Federation (126 individuals from 18 sports) performed countermovement-jump and Keiser tests on 2 to 11 occasions between 2014 and 2021. Separate analyses were performed for male and female alpine skiing, male and female handball, male ice hockey, and males and females of other sports. Means and standard deviations of consecutive change scores were combined with short-term error of measurement (3.7%–7.0%) and smallest important changes (2.0%–3.6%, defined by standardization) to determine the proportions of athletes who experienced decisive changes in 2 senses: first, the athlete did not get substantially worse or better (>90% chance of either), and second, the athlete did get substantially worse or better (>90% chance of either). Results: Averaged over sports, Keiser peak power and relative peak power had the highest proportions of decisive changes in the first (60% and 55%) and second senses (25% and 28%). The velocity intercept of the force–velocity relationship had the lowest proportions in the first and second senses (29% and 11%), while jump height, Keiser mean power, relative mean power, the force intercept, and the slope of the force–velocity relationship had similar proportions (40%–53% and 15%–21%). Conclusions: With the possible exception of the Keiser test velocity intercept, the proportions of observed decisive changes in elite athletes using Keiser measures and countermovement-jump height between tests appear adequate for the measures to be useful for routine monitoring. [ABSTRACT FROM AUTHOR]

Objective: Individual unsupervised home-based exercise programs can enhance muscle strength, physical function, gait, and balance in older adults. However, the effectiveness of such programs may be limited by the lack of supervision. This study aims to verify the effectiveness of individual unsupervised home-based programs, compare the effects of individual unsupervised home-based to supervised programs, and verify the influence of supervision over individual unsupervised home-based programs on the physical function of older adults. Methods: A systematic literature search was performed in four electronic databases, and the trials involved randomized controlled comparing the home-based programs to supervised, control groups, or home-based + supervised evaluating the muscle strength, physical function, gait, and balance in older adults. Results: Eleven studies met the inclusion criteria. The meta-analysis revealed no differences between home-based program versus supervised program in gait, mobility, and balance, revealing a trend of significance to supervised program on strength (standardized mean difference [SMD] = 0.27, p =.05). The analysis revealed effects in mobility (SMD = 0.40, p =.003), balance (SMD = 0.58, p =.0002), and muscle strength (SMD = 0.36, p =.02) favoring home-based program versus control group. Significant effects between home-based program versus home-based + supervised program were observed in balance (SMD = 0.74, p =.002) and muscle strength (SMD = 0.58, p =.01) in favor of home-based + supervised program. Conclusion: Home-based programs effectively improve older adults' physical function compared with control groups. However, supervised programs were more effective for muscle strength. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analyze the criterion‐related validity and the reliability of the standing long jump test (SLJ) for evaluating the lower‐body explosive muscular strength in adults. A total of 410 adults participated in this study. Sociodemographic, anthropometric measurements, laboratory lower‐body muscular strength tests, and the field‐based SLJ were performed. In validity analysis, stepwise regression analysis showed that maximal horizontal power, sex, percentage of body fat, maximal horizontal force, and lean mass were significantly associated with the SLJ distance (R2 = 0.78; p < 0.001). Reliability analysis showed significant differences between test–retest in the SLJ test, with an overestimation of the second measurement compared to the first [12.14 ± 14.46 cm, intraclass correlation coefficient (ICC) = 0.94 (0.75–0.97), p < 0.001; Cohen's d = 0.31]. The coefficient of variation (CV) was 7.06% and the minimal detectable change (MDC90) was 29 cm. After a learning period, higher reliability values were found [0.45 ± 1.04 cm, ICC = 1.00 (0.99–1.00); p = 0.001; CV = 0.53 %; MDC90 = 1 cm]. The SLJ test may be a valid tool to assess lower‐body explosive muscular strength in the adult population. A learning period may be necessary to provide reliability on the SLJ test. Highlights: The standing long jump (SLJ) test is the most used field‐based test for assessing lower‐body explosive muscular strength. However, its criterion‐related validity and reliability have not been explored in the adult population.The SLJ is a valid test. Maximal horizontal power, sex, percentage of body fat, maximal horizontal force, and lean mass account for validity variance in SLJ distance.The SLJ test is a reliable tool, regardless of sex, age and physical activity levels. It may be beneficial to implement a familiarization period before evaluation to ensure reliability.The SLJ test is practical, time‐efficient, and low in cost and equipment requirements. [ABSTRACT FROM AUTHOR]

Change of directions (COD) involves multidirectional and complex actions, with performance influenced by multiple factors. As lower limb strength is one of the most determinant of COD performance, the present study aimed to (a) explore the differences in strength outcomes across different lower limb muscle actions between faster and slower basketball players in COD actions at different angles and (b) analyse the relationship between isometric, concentric and eccentric strength outcomes and COD performance at different cutting angles. Twenty‐five basketball players (44% female) completed a battery of tests, encompassing isokinetic and isometric squat strength assessments, along with COD tests at 45°, 90° and 180°. Players were categorised as 'low‐performance' and 'high‐performance' groups based on execution time in COD, facilitating a comparison between performance groups. Results indicated that concentric strength showed the greatest differences between performance groups at 45° COD (effect size ≥ 0.813; p ≤ 0.034). Isometric and eccentric strength demonstrated a moderate‐to‐large relationship with 90° COD performance (Rho ≥ 0.394; p ≤ 0.045), and all muscle actions exhibited a large relationship with 180° COD (Rho ≥ 0.445; p ≤ 0.030). Moreover, the fastest players showed higher levels of concentric strength relative to eccentric strength, regardless of the cutting angle. These findings hold practical applications, suggesting that basketball coaches should train a specific kind of muscle action depending on the individual players' COD demands, focusing on improving the rapid eccentric force application while striving to reduce the eccentric/concentric ratio. Highlights: Strength is undeniably a key indicator in change of directions (COD) performance. The relationship between strength outcome measures and COD proficiency depends on the cutting angle.Cutting angles below 90° emphasise concentric strength, while those above 90° exhibit a stronger reliance on isometric and eccentric strength.Rapid eccentric force production strongly correlates with COD performance across all cutting angles. However, the fastest players exhibit higher concentric strength relative to their eccentric strength. [ABSTRACT FROM AUTHOR]

A novel fixation system for a hand‐held dynamometer (HHD) was designed to enable isometric muscle measurements on various muscle groups of strong, healthy individuals in a field setting. The objective of this study was to evaluate the intra‐ and interrater reliability of the system and determine its suitability for use by multiple researchers within large‐scale data collections during field activities. Four researchers tested eight healthy subjects, who each completed eight different maximal isometric muscle strength assessments using the HHD fixation system. Intraclass correlation coefficients (ICC) results were evaluated with a 95% confidence interval. ICC results for interrater reliability demonstrated excellent agreement of all eight measurements tested. ICC results for intrarater reliability demonstrated excellent agreement for six out of eight measurements. This system provides a new opportunity for several different high‐quality maximal muscle strength measurements to be collected by multiple data collectors on large numbers of strong, healthy individuals in a field setting. Highlights: This system is a reliable testing procedure that provides a new opportunity for several different high‐quality maximal muscle strength measurements.The system allows for laboratory quality data to be collected in the field by multiple data collectors on large numbers of strong, healthy individuals. [ABSTRACT FROM AUTHOR]

Purpose: Prior evidence has shown that neural factors contribute to the loss of muscle force after skeletal muscle disuse. However, little is known about the specific neural mechanisms altered by disuse. Persistent inward current (PIC) is an intrinsic property of motoneurons responsible for prolonging and amplifying the synaptic input, proportionally to the level of neuromodulation, thus influencing motoneuron discharge rate and force production. Here, we hypothesized that short-term unilateral lower limb suspension (ULLS) would reduce the neuromodulatory input associated with PIC, contributing to the reduction of force generation capacity. In addition, we tested whether physical exercise would restore the force generation capacity by reestablishing the initial level of neuromodulatory input. Methods: In 12 young adults, we assessed maximal voluntary contraction pre- and post-10 d of ULLS and after 21 d of active recovery (AR) based on resistance exercise. PIC was estimated from high-density surface electromyograms of the vastus lateralis muscle as the delta frequency (ΔF) of paired motor units calculated during isometric ramped contractions. Results: The values of ΔF were reduced after 10 d of ULLS (-33%, P < 0.001), but were fully reestablished after the AR (+29.4%, P < 0.001). The changes in estimated PIC values were correlated (r = 0.63, P = 0.004) with the reduction in maximal voluntary contraction after ULLS (-29%, P = 0.002) and its recovery after the AR (+28.5%, P = 0.003). Conclusions: Our findings suggest that PIC estimates are reduced by muscle disuse and may contribute to the loss of force production and its recovery with exercise. Overall, this is the first study demonstrating that, in addition to peripheral neuromuscular changes, central neuromodulation is a major contributor to the loss of force generation capacity after disuse, and can be recovered after resistance exercise. [ABSTRACT FROM AUTHOR]

Beetroot juice supplementation (BRJ) should increase nitric oxide bioavailability under conditions of muscle deoxygenation and acidosis that are a normal consequence of the maximal effort exercise test used to identify forearm critical impulse. We hypothesized BRJ would improve oxygen delivery:demand matching and forearm critical impulse performance. Healthy males (20.8 ± 2.4 years) participated in a randomized crossover trial between October 2017 and May 2018 (Queen's University, Kingston, ON). Participants completed 10 min of rhythmic maximal effort forearm handgrip exercise 2.5 h post placebo (PL) vs. BRJ (9 completed PL/BRJ vs. 4 completed BRJ/PL) within a 2 week period. Data are presented as mean ± SD. There was a main effect of drink (PL > BRJ) for oxygen extraction (P = 0.033, ηp2 = 0.351) and oxygen consumption/force (P = 0.017, ηp2 = 0.417). There was a drink × time interaction (PL > BRJ) for oxygen consumption/force (P = 0.035, ηp2 = 0.216) between 75 and 360 s (1.25–6 min) from exercise onset. BRJ did not influence oxygen delivery (P = 0.953, ηp2 = 0.000), oxygen consumption (P = 0.064, ηp2 = 0.278), metabolites ((lactate) (P = 0.196, ηp2 = 0.135), pH (P = 0.759, ηp2 = 0.008)) or power-duration performance parameters (critical impulse (P = 0.379, d = 0.253), W′ (P = 0.733, d = 0.097)). BRJ during all-out handgrip exercise does not influence oxygen delivery or exercise performance. Oxygen cost of contraction with BRJ is reduced as contraction impulse is declining during maximal effort exercise resulting in less oxygen extraction. [ABSTRACT FROM AUTHOR]

The aims of the study were to build models using logistic regression analysis of flexibility and strength tests to prospectively predict risk factors for anterior cruciate ligament tear (ACL-tear) in female soccer (FS) players, and to determine training cut-off for risk factors of the predictive model built. A prospective cohort study of 95 female players (aged 14–33 years) was conducted. Age, anthropometric data, soccer history, lower limb range of motion (ROM) and hip maximal isometric strength (MIS) were measured. At the prospective follow-up after 12 months, 7.4% of the players had developed an ACL-tear. The model showed a significant relationship (χ2(93) = 30.531, p < 0.001) between the ACL-tear and the predictor variables (leg length, HAD-NH [hip adduction] MIS, asymmetric ROM [ankle dorsiflexion with knee extended (AD-KE) and with knee flexed (AD-KF), and HE (hip extension)], hip ROM [HIR (internal rotation) and HAB (abduction)]). The Akaike Information Criteria (AIC) and Bayesian Information Criteria (BIC) for model fit were 30.24 and 51.79, respectively. The value R2 showed good model fit, 76.5% for Nagelkerke´s R2, 71.4% for McFadden´s R2 and 67.5% for Tjur´s R2. For the screening test, cut-off for leg length of ≥0.40 m, for HIR ROM of ≤44º and for asymmetry of HE ROM of ≥5° were set, which have an acceptable (AUC ≥ 0.755) discriminatory ability for the development of ACL-tear. [ABSTRACT FROM AUTHOR]

Background and objective: Iron deficiency affects more than 60% of colorectal cancer patients at the time of diagnosis. Iron deficiency ultimately leads to anemia, but additionally, iron deficiency might impact other domains of colorectal cancer patients' health and well-being. The aim of this study was to evaluate the impact of iron deficiency on fatigue, quality of life, cognition, and physical ability in patients undergoing evaluation for colorectal cancer. Methods: Multicenter, prospective, observational cross-sectional study (2021–2023). Fatigue was the primary outcome, measured using the Focused Assessment of Cancer Treatment-Anemia questionnaire (FACT-An). Quality of Life, Cognition, Aerobe capacity, mobility, and peripheral muscle strength were tested as secondary outcomes. Multivariate analysis was performed to estimate the impact of iron deficiency on all outcomes. Results: Two hundred and one patients were analyzed, 57% being iron deficient. In multivariate regression analysis, iron deficiency was not associated with fatigue: FACT-An (r = −1.17, p = 0.57, 25% CI: −5.27 to 2.92). Results on quality of life, cognition, and mobility were non-significant and with small regression coefficients. Iron deficiency showed a nearly significant association with reduced hand-grip-strength (r = −3.47 kg, p = 0.06, 25%CI −7.03 to 0.08) and reduced 6 min walking distance (r = −40.36 m, p = 0.07, 25%CI: −84.73 to 4.00). Conclusion: Iron deficiency in patients undergoing evaluation for colorectal cancer was not associated with fatigue, quality of life, or cognition, but might affect aerobic endurance and peripheral muscle strength to a degree that is clinically relevant. [ABSTRACT FROM AUTHOR]

BACKGROUND: People with forward head posture (FHP) and rounded shoulder posture (RSP) may experience shifts in scapular position and alterations in the strength of the muscles surrounding the scapula. Therefore, a reliable scapula position and scapula muscle strength test are required to identified scapula problem and provided appropriate intervention programs. OBJECTIVE: This study aimed to determine the reliability of scapular position measurements obtained using a modified digital inclinometer and palpation meter, as well as muscle strength using a hand-held dynamometer (HHD) in individuals with FHP and RSP. METHODS: Thirty healthy subjects underwent scapular position tests (upward rotation, anterior tilt, depression, and protraction) and strength tests of periscapular muscles (serratus anterior, upper trapezius, middle trapezius, and lower trapezius) on both the dominant and non-dominant sides. The reliability of the measurements was confirmed by computing the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal clinically important difference (MCID). Test and re-tests were conducted over a period of one week and actual values for each measurement were also obtained and assessed. RESULTS: The ICC ranged from 0.802 to 0.935 for the scapular position tests and from 0.808 to 0.949 for muscle strength tests on the dominant and non-dominant sides. For scapular position tests, SEM values ranged from 0.3 cm to 0.6 cm (protraction and depression), from 1.0∘ to 1.7∘ (upward rotation and anterior tilt) and MCID values ranged from 0.7 cm to 1.6 cm (protraction and depression), from 2.8∘ to 4.7∘ (upward rotation and anterior tilt). Regarding muscle strength tests, SEM and MCID values were in the range 14.4N–27.3N and 39.9N–75.7N, respectively. CONCLUSIONS: Scapular position and periscapular muscle strength can be reproducibly measured in healthy subjects individuals with FHP and RSP. These instruments can hence be recommended for evaluating these functional traits in subjects with FHP and RSP. [ABSTRACT FROM AUTHOR]

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Purpose Methods Results Conclusions Level of Evidence This study investigates the clinical and activity‐based outcomes after anterior cruciate ligament reconstruction (ACLR) versus multiligamentous knee reconstruction (MLKR) following a pivoting sports injury.Fifty MLKR patients were included, of which 20 (40%) were injured during pivoting sports. A further 50 patients undergoing ACLR following an injury during pivoting sports were consecutively recruited for comparison. Patients were assessed before the surgery and at 6‐, 12‐ and 24 months with patient‐reported outcome measures (PROMs) including the International Knee Documentation Committee (IKDC) form, Tegner activity scale (TAS) and anterior cruciate ligament return to sport after injury (ACL‐RSI) score. Knee movement, the single (SHD) and triple (THD) hop tests for distance, and peak isokinetic knee extensor and flexor strength were assessed, with Limb Symmetry Indices (LSIs) calculated. Outcomes were compared across groups: (1) ACLR (n = 50), (2) MLKR (n = 50) and (3) MLKR due to pivoting sport injury (n = 20).IKDC, TAS and ACL‐RSI scores remained lower (p < 0.05) in the full MLKR versus ACLR cohort at all timepoints. Comparing the ACLR and MLKR cohort that had injuries specifically during pivoting sports, the IKDC (p < 0.001) and TAS (p = 0.009) were higher in the ACLR group at 6 months, and the ACL‐RSI was higher at 6 (p < 0.001) and 12 (p = 0.007) months, there were no further differences. Hop and knee extensor strength LSIs were lower (p < 0.05) in the full MLKR (versus ACLR) cohort at all timepoints (apart from the 24‐month SHD LSI). However, the ACLR group only demonstrated greater LSIs than the pivoting sport MLKR for the SHD at 6 months (p < 0.001), and knee extensor strength at 6 (p < 0.001) and 12 (p < 0.001) months.While the recovery of patients undergoing MLKR due to a pivoting sports injury is delayed compared with their ACLR counterparts, the clinical outcome and activity profile are similar by 24 months.Level IV. [ABSTRACT FROM AUTHOR]

Performance in intermittent sports relies on the interplay between multiple physiological systems determining the capacity to perform short explosive efforts as well as repeated intense actions with limited recovery over the course of an entire game. Testing should reflect these demands to allow for sport- and position-specific capacity analyses that eventually may translate into optimized training and improved performance. This may include individual loadmanagement and optimized training prescription, intensity targeting for specific positions or individual athletes, as well as benchmarking for monitoring of training progression and enhanced engagement of athletes. This review provides an overview of available tests in different exercise domains identified as relevant (fromassessment of single explosive actions to intermittent endurance capacity), forming the basis for recommendations on how to compose a comprehensive yet feasible test battery that may be integrated into the seasonal competition and training plan. The test procedures should cover the performance spectrum of relevance for the individual athlete--also in team sports to account for positional differences. We emphasize the benefits of sport-specific tests, highlight parameters of importance for test standardization, and discuss how the applied test battery may be supplemented with secondary tests directed toward specific energy systems to allow formore in-depth analyses when required (e.g., in terms of an underperforming athlete). The synergy between testing and tracking of match performance (utilizing time-motion or global positioning systems) is highlighted, and although tracking cannot substitute for testing, combining the tools may provide a comprehensive overview of the physiological demands and performance during competition contextualized to the athletes' maximal exercise capacity. [ABSTRACT FROM AUTHOR]

Introduction: The war caused huge devastation to rehabilitation centers in Mosul City, leading to a significant gap in rehabilitation services, which was further compounded by the COVID-19 pandemic. Objectives: We sought to incorporate simple and safe clinical exercises by utilizing common household items, thereby maximizing effectiveness through a combination of psychological simulation and physical impact while ensuring safety, and evaluate its efficacy as a home telerehabilitation program (HTRP) for participants with spinal cord injury (SCI) following a 4- to 5-year rehabilitation interruption. Methods: Eighteen volunteers, including 13 with SCI (injuries sustained 53.4–55 months prior), were split into an experimental group (Exp., n = 8), a first control group (first Con., n = 5), and a second control group of healthy individuals (second Con., n = 5), averaging 21.2 years old. The HTRP focused on muscles and whole-body joints, conducted with five weekly sessions gradually increasing from 45 to 120 min, with sufficient rest. Assessments occurred every 3 months. Results: The Friedman test indicated no significant effect of HTRP on weight, body mass index, 3 of 4 anthropometric measures, and 4 of 19 muscle strength tests, p > 0.05, and small effect sizes (ES). However, significant effects were observed in pelvic strength (p < 0.001, ES = 0.73), exceeding control groups (first Con. 1.6%, second Con. 1.0%). Muscle strength in the lower extremities, head, and trunk showed significant improvements (p < 0.05, ES = 18.3–81.8%), it is indicating functional enhancement despite morphological weaknesses, particularly in individuals with SCI. Conclusion: The HTRP demonstrated weak effects on muscle morphology but strong effects on functionality, highlighting its potential for long-term management and improvement of muscle functional outcomes in individuals with SCI, even after prolonged rehabilitation interruptions. [ABSTRACT FROM AUTHOR]

This study aimed to develop and assess a protocol for evaluating upper limb strength and its association with functional abilities in children and adolescents diagnosed with Duchenne muscular dystrophy (DMD). A cross-sectional study. Eleven male individuals diagnosed with DMD (aged 11 to 18 years). A systematic protocol for assessing the maximum voluntary isometric contraction (MVIC) of the upper limbs using grip and pull dynamometers was developed and conducted in conjunction with the Performance of Upper Limb (PUL) scale. Feasibility was evaluated by appraising the number of participants capable of successfully executing the strength test protocol. Correlations were conducted to examine the relationship between upper limb strength and PUL scores. The grip strength assessment was feasible for all participants, while the complete strength testing protocol was feasible for nine, excluding two individuals with non-ambulatory mobility. Significant correlations were found between overall upper limb strength and total PUL scores (rs = 0.742, p = 0.022), grip strength and distal PUL scores (rs=0.733, p = 0.010), shoulder abduction strength and PUL shoulder scores (rs=0.905, p = 0.005), and grip strength and overall PUL scores (rs=0.794, p = 0.004). The middle-level correlation was not statistically significant (rs=0.590, p = 0.094). The established strength test protocol demonstrated feasibility among ambulatory participants. However, alternative approaches are essential for those with limited ambulation. The study identified a robust correlation between upper limb strength and functional abilities. Further extensive studies are required to validate these findings. The present study is a part of a longitudinal intervention study registered at the ClinicalTrials.gov (NCT03963453). [ABSTRACT FROM AUTHOR]

The purpose of this pilot study was to explore the acute effect of upper-body and lower-body neuromuscular fatigue protocols on baseball pitchers' velocity. Sixteen baseball pitchers were recruited, and a crossover design was used to meet the study purpose. Pitchers were tested twice, 7 days apart, with their upper-body and lower-body explosiveness, pitching velocity, and muscle soreness perception of their throwing arm (forearm flexors, biceps, anterior deltoid, and upper trapezius muscles) assessed before and after an upper-body and lower-body neuromuscular fatigue protocol. Two-way analysis of variances and paired t tests (p < 0.05) were used to identify and compare prescores and postscores. Following both fatigue protocols, results revealed a significant decrease in time for pitching velocity (p = 0.005, ηp² = 0.462), and increases in muscle soreness perception of the forearm flexors (p = 0.005, ηp² = 0.470), anterior deltoid (p = 0.045, ηp² = 0.274), and upper trapezius (p = 0.023, ηp² = 0.339) muscles. Paired t test results showed a significant decrease in preneuromuscular and postneuromuscular fatigue protocol in the upper-body (p < 0.01) and lower-body (p < 0.01) explosiveness scores. These pilot study results show the impact of different exercise protocols on pitchers' explosiveness, velocity, and muscle soreness perception emphasizing the need for further investigation into the acute effect of exercise targeting the upper or lower-body on pitching performance, specifically at the pitcher's position. [ABSTRACT FROM AUTHOR]

This study aimed to explore the feasibility and face validity of predicting maximum strength 1 repetition maximum (1-RM) and 4-6 RM in athletes across different sports specialties, based on the relationship between muscle strength and BM. One hundred fifteen male athletes, aged 23.63 ± 6.77 years and participating in diverse sports specialties, were included in this study. Muscle strength was assessed using the 4-6 RM and 1-RM tests in free-weight bench press (BP) and Smith machine squat (SQ) exercises, whereas BM was measured using a portable digital scale. A linear regression equation based on muscle strength and BM was performed. The 4-6 RM and 1-RM scores showed excellent intersession relative reliability (intraclass correlation coefficient(2,1): 0.946-0.989) and absolute reliability (CV: 3.4-4.7%) in both BP and SQ exercises. In addition, the magnitude of the relationship and the coefficients used to estimate the 4-6 RM and 1RM, based on BM, differed among the subjects when they are grouped according to their sports specialties (R² ranged from non-significant to 0.998). Overall, the 4-6 RM test showed a stronger correlation with BM (R: 0.655 for SQ and R: 0.683 for BP) than the 1RM (R: 0.552 for SQ and R: 0.629 for BP), and the general (i.e., not sport-specific) 4 to 6-RM prediction equations should be preferred over sport-specific ones because they are statistically more robust due to the larger sample size. In conclusion, the 4-6 RM can be predicted from BM with high reliability, a moderate association, and a prediction error that, when considering the 4-6 RM as a starting point for estimating of the 1RM, can be considered entirely acceptable in practical settings. [ABSTRACT FROM AUTHOR]

The objective of this study is to describe how flywheel exercise mechanical outputs are affected by the athletes' body mass (BM) and strength level and by the exercise type. Forty-six recreational athletes came to a laboratory 3 times. On the first day, descriptive data, squat (1 repetition maximum: 1RM) and flywheel familiarization were performed. After a second day of familiarization, subjects performed a randomized flywheel exercise-testing protocol of squat and split squat exercises. The variables used for data analysis were peak concentric power and peak eccentric power, eccentric/concentric ratio, and their relationship with 1RM/BM. Subjects were assigned to a stronger or weaker group according to their 1RM/BM ratio. Group differences were found in absolute values of eccentric overload (EOL) (p < 0.01; effect size [ES] = 0.51) and EOL/BM (p < 0.01; ES = 0.46) only in the split squat. Absolute power values in the concentric phase showed differences between inertial load (p < 0.01; ES = 0.41). The stronger group did not present significant differences between inertial loads during squat (p < 0.01; ES = 0.46), but they showed different ratios with light inertias in comparison with the weaker group (p < 0.01; ES = 0.46). There were significant differences between groups with light inertias in split squat (nondominant) and squat exercises (p < 0.05; ES = 0.29) in the eccentric and concentric phases (p < 0.116; ES = 0.20). Squat and split squat exercises present different profiles depending on the training level. In conclusion, it is recommended that practitioners perform a test to understand the inertial load-power profile (concentric, eccentric, and their ratio) for each exercise and also consider the user's strength level for selection of the inertial load and for the exercise to use in training. [ABSTRACT FROM AUTHOR]

Purpose: Patients with abdominal rectus diastasis (ARD) may have muscular functional impairments, but clinics lack appropriate objective assessment tools. The aim was to establish the relative and absolute reliability, and convergent validity, of muscular activity using Surface Electromyography (SEMG) during isometric abdominal muscle strength testing in patients with ARD and controls without ARD. Methods: Twenty-six patients with ARD were matched for age, sex and BMI with controls without ARD. Participants were tested twice during isometric muscular contractions using SEMG located on six abdominal sites. Mean amplitude, fatigue, and recruitment order were analyzed. Relative reliability was evaluated with Intraclass Correlation Coefficients (ICC), while absolute reliability was estimated by calculating the Standard Error of Measurement and Minimal Detectable Change. Convergent validity was addressed in relation to participant characteristics, functional ability, and symptoms. Results: Mean SEMG amplitude for all abdominal wall muscle contractions showed moderate to excellent relative test–retest reliability, with ICC values ranging from 0.46 to 0.97. In contrast, fatigue and recruitment order displayed poor to moderate relative reliability in both groups. Absolute reliability measures were generally high. A moderate to high convergent validity (ARD: rho-value 0.41–0.70; Controls: rho-value 0.41–0.75) was observed for mean amplitude in relation to a functional sit-to-stand test, abdominal circumference, BMI, back pain, and quality-of-life. Conclusions: The results of applying SEMG during isometric abdominal muscle support practicing the method in clinics, although additional development is needed with further standardization and more functional testing. Furthermore, the method demonstrates construct validity in patients with ARD and in age- and sex-matched controls. [ABSTRACT FROM AUTHOR]

Purpose: Older adults frequently encounter health challenges, such as impaired balance and muscle health, which increase risk of falls. The current study investigated the effectiveness of the proprioceptive neuromuscular facilitation (PNF) technique in improving balance and muscle health among older adults with high fall risk. Method: A total of 160 older adults with high fall risk were randomized into control and intervention groups. Over 6 months, the control group received standard interventions, while the intervention group received the same interventions and additional PNF training. Results: Both groups demonstrated improvements in balance function over time, with the intervention group exhibiting significant improvements in Berg Balance Scale scores, Timed Up and Go test times, and 30-Second Chair Stand Test counts (p < 0.05). Bone density significantly increased in the intervention group compared to the control group (p < 0.05), although no substantial differences in lower limb muscle mass were observed. Satisfaction rates were higher and fall incidents fewer in the intervention group. Conclusion: The PNF technique is effective in enhancing balance function and muscle health in older adults with high fall risk, demonstrating potential in reducing fall risk and improving quality of life among older adults. [Journal of Gerontological Nursing, 50(8), 37–44.] [ABSTRACT FROM AUTHOR]

Background and Objectives: Frailty in older adults is associated with adverse health outcomes. This study aimed to analyze the frailty status of community-dwelling older adults in Taiwan using the Kihon Checklist (KCL) and explore associations with demographic, physiological, and functional factors. Materials and Methods: In this cross-sectional study, 278 community-dwelling older adults were classified as robust, prefrail, or frail based on their KCL scores. Participants underwent physical fitness assessments including muscle strength and endurance tests, walking speed tests, and flexibility tests. One-way ANOVA and logistic regression analyses were used to examine differences and associations between frailty status and physical fitness indicators. Results: 36% of participants were robust, 47.1% prefrail, and 16.9% frail. The robust group significantly outperformed the prefrail and frail groups in the 30 s sit-to-stand test, 2.44 m sit-to-walk test, and walking speed (p < 0.001). The 2.44 m sit-to-walk test was a significant predictor of prefrailty (OR = 1.18, 95% CI = 1.02–1.36) after adjusting for other physical fitness indicators. Conclusions: Lower limb functional capacity, particularly in the 2.44 m sit-to-walk test, was significantly associated with pre-frailty among community-dwelling older adults in Taiwan. Early screening, the classification of frailty by the Kihon Checklist, and targeted interventions focusing on lower limb strength, endurance, and mobility are crucial for preventing and delaying frailty progression in older populations. [ABSTRACT FROM AUTHOR]

Among the graft options for anterior cruciate ligament reconstruction (ACLR), hamstring autografts are widely regarded as the preferred choice for primary ACLR among orthopedic surgeons worldwide. However, concerns persist regarding postoperative knee flexor weakness. We aimed to compare knee extensor and flexor strengths between hamstring autograft and tibialis anterior allograft groups in ACLR patients, who were propensity score-matched based on baseline characteristics. A retrospective analysis included 58 matched pairs who underwent isokinetic strength tests at 6 and 12 months post operation. Isokinetic muscle strength tests found no significant difference in knee extensor and flexor strength at 6 months post operation between the hamstring autograft and tibial anterior allograft groups. At 12 months, the hamstring autograft group exhibited significantly greater knee flexor deficit (total work and average power) compared to the allograft group, despite no differences in extensor strength or patient-reported outcomes. This study highlights the impact of hamstring autograft harvesting on muscle strength and recovery following ACLR in short-term period. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the effects of exercise training (ET) and inspiratory muscle-loaded exercise training (IMLET) on ventilatory response and intercostal muscle deoxygenation levels during incremental cycling exercise. Methods: Twenty-one male participants were randomly divided into IMLET (n = 10) or ET (n = 11) groups. All participants underwent a 4-week cycling exercise training at 60% peak oxygen uptake. IMLET loaded 50% of maximal inspiratory pressure (PImax). Respiratory muscle strength test, respiratory muscle endurance test (RMET), resting hypoxic ventilatory responsiveness (HVR) test, and incremental cycling test were performed pre- and post-training. Results: The extent of improvement in the PImax was significantly greater in the IMLET group (24%) than in the ET group (8%) (p = .018), and an extended RMET time was observed in the IMLET group (p < .001). Minute ventilation (${\dot V_E}$V˙E) during exercise was unchanged in both groups before and after training, but tidal volume during exercise increased in the IMLET group. The increase in the exercise intensity threshold for muscle deoxygenation was similar in both groups (p < .001). HVR remained unchanged in both groups post-training. The exercise duration for the incremental exercise until reaching fatigue increased by 7.9% after ET and 6.9% after IMLET (p < .001). Conclusion: The 4-week IMLET improved respiratory muscle strength and endurance but did not alter HVR. Respiratory muscle deoxygenation was alleviated by exercise training, with a limited impact of inspiratory load training. [ABSTRACT FROM AUTHOR]

Preparing athletes for competition requires the diagnosis and monitoring of relevant physical qualities (e.g., strength, power, speed, endurance characteristics). Decisions regarding test selection that attempt to measure these physical attributes are fundamental to the training process yet are complicated by the myriad of tests and measurements available. This article presents an evidenced based process to inform test measurement selection for the physical preparation of athletes. We describe a method for incorporating multiple layers of validity to link test measurement to competition outcome. This is followed by a framework by which to evaluate the suitability of test measurements based on contemporary validity theory that considers technical, decision-making, and organisational factors. Example applications of the framework are described to demonstrate its utility in different settings. The systems presented here will assist in distilling the range of measurements available into those most likely to have the greatest impact on competition performance. [ABSTRACT FROM AUTHOR]

This study investigates individual performance adaptations on 2 years of training between European Aerobics Championships. An elite, 22-year-old aerobic gymnast performed postural coordination test, Y-Balance test, squat and countermovement jumps, 60 s test of repeated jumps, an isokinetic leg muscle strength test, and the Wingate test. Postural stability and flexibility improved in terms of increased distance achieved in the Y-Balance test in the anterior (by 6.3%), posteromedial (by 2%), and posterolateral (by 4.8%) directions. Lower limb muscular endurance also increased, which can be corroborated by a reduced fatigue index in the 60 s test of repeated jumps (from 42% to 27% after the 1st and to 22% after the 2nd year of training). In addition, mean power increased during dominant (by 23.2% at 60°/s and by 18.5% at 180°/s) and non-dominant leg extension (by 4.9% at 180°/s and by 15.5% at 300°/s), plus dominant leg flexion (by 2.0% at 60°/s and by 6.9% at 300°/s). Similarly, peak torque/body weight ratio increased during dominant (by 24.9% at 60°/s, by 11.5% at 180°/s, and by 2.1% at 300°/s) and non-dominant leg extension (by 0.5% at 60°/s and by 6.4% at 300°/s), plus dominant leg flexion (by 1.7% at 60°/s and by 5.4% at 300°/s). However, 2 years of training failed to show any significant improvements in the explosive power of lower limbs and anaerobic performance. These findings indicate that general aerobic gymnastics training without any specific inputs leads to performance adaptation, namely, in abilities closely related to competition routine (dynamic balance and strength endurance of lower limbs). [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to examine the test−retest reliability in lower limb muscle strength and rate of torque development (RTD) using isokinetic dynamometry in adults with obesity, with a body mass index (BMI) ≥ 35 kg/m2. Method: Thirty‐two adults with a BMI of 43.8 ± 6.6 kg/m2 eligible for bariatric surgery were enroled in the study. Isokinetic and isometric knee extensor (KE) and flexor (KF) strength were assessed in an isokinetic dynamometer (Biodex 4) during three test sessions separated by 3−7 days. Results: There were no statistical differences in peak KE and KF torque for any test modalities between sessions. Intraclass correlation (ICC) was 0.91−0.94 between sessions 1 and 2 and 0.94−0.97 between sessions 2 and 3. Standard error of measurement (SEM%) and coefficient of variation (CV) ranged across test sessions from 4.3% to 7.3%. KE RTD showed high test−retest reliability following familiarization, with ICC, CV and SEM% values ranging from 0.84 to 0.90, 13.3%−20.3% and 14.6%−24.9%, respectively. Conclusion: Maximal lower limb muscle strength measured by isokinetic dynamometry showed excellent test−retest reliability manifested by small measurement errors and low CV. Reliability was slightly improved by including a familiarization session. KE RTD but not KF RTD demonstrated high test−retest reliability following familiarization. The present data indicate that isokinetic dynamometry can be used to detect even small changes in lower limb muscle strength in adults with obesity. [ABSTRACT FROM AUTHOR]

Previous studies reported inconsistent outcomes on elastic taping for three potential reasons: 1) poor control of placebo effect; 2) no consensus regarding the optimal tape tension; and 3) lack of investigation on muscle endurance, as the proposed tape recoiling force may not promote peak force generation but exert a consistently low force and improve submaximal contraction. This study compared the effects of elastic tape and its tension on muscle activity and endurance in people with extremely positive and negative personal belief on elastic tape. Using a validated instrument, we identified 20 participants with extremely positive personal belief on elastic tape (+ belief), and 20 with extremely negative personal belief (- belief). They performed wrist isometric endurance tests under three taping conditions (i.e. no tape, 50%, and 100% tension). We measured isometric wrist extensor muscle endurance, electromyography muscle activity, and self-perceived performance for each condition. The differences between the two groups in isometric muscle endurance (p =.85) and muscle activity (p =.53) were not statistically significant, regardless of tape conditions. However, participants with + belief reported better perceived performance than those with – belief (p <.001, partial eta squared = 0.70). Specifically, 100% tape tension yielded stronger self-perceived performance than 50% tension (Cohen's d = 0.91) and no tape (Cohen's d = 1.86). On the other hand, participants with – belief perceived similar performance across tape tensions (p =.55). Elastic tape does not modulate muscle activity and enhance muscle endurance. People with a strong positive personal belief on elastic tape may perceive a better performance with a greater tape tension. [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]

Background: A disadvantage of using hamstring tendon autograft consisting of the semitendinosus and gracilis tendons for anterior cruciate ligament reconstruction is pain from tendon harvesting and persistent hamstring weakness. In the tendon-sparing all-inside technique, a quadrupled semitendinosus graft and adjustable-loop cortical fixation are suggested to give less postoperative flexion deficits while displaying overall similar clinical results to the traditional hamstring technique. However, there are a limited number of high-quality studies comparing these techniques with inconsistent results. Purpose: To investigate differences between the all-inside (quadrupled semitendinosus) and traditional hamstring (double-stranded semitendinosus and gracilis) technique regarding (1) self-reported function, (2) hamstring strength, and (3) knee laxity. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 98 patients were randomized to either the all-inside or the traditional hamstring technique. Perioperatively, duration of surgery and graft size were obtained. The International Knee Documentation Committee 2000 Subjective Knee Form score, Knee injury and Osteoarthritis Outcome Score, Tegner Activity Scale score, knee laxity (KT-1000 arthrometer side-to-side difference and pivot shift), range of motion, isokinetic knee strength, and hop test score were collected preoperatively and 2 years postoperatively. Return-to-sport readiness was evaluated 9 months postoperatively. Results: A total of 89 patients completed 2-year follow-up, 45 patients with the all-inside technique and 44 patients with the traditional hamstring technique. There were no significant differences between groups in any of the outcome measures 2 years after surgery, but there was a tendency in the all-inside group toward having increased anterior translation (mean, 3.6 mm vs 2.7 mm), a higher number of revision surgeries (5 patients vs 2 patients), and more patients having +1 and +2 pivot-shift values (29 vs 18 patients) when compared with the traditional group. Conclusion: The all-inside technique yields equivalent results to the traditional hamstring technique 2 years after surgery and should be considered a reliable technique to use for ACL reconstruction. Sparing the gracilis tendon does not lead to less persistent hamstring weakness. Long-term follow-up is needed to further determine whether the tendency of increased anterior translation seen at 2 years postoperatively will lead to a higher risk of graft failure. [ABSTRACT FROM AUTHOR]

Background and purpose: Because Becker muscular dystrophy (BMD) is a heterogeneous disease and only few studies have evaluated adult patients, it is currently still unclear which outcome measures should be used in future clinical trials. Methods: Muscle magnetic resonance imaging, patient‐reported outcome measures and a wide range of clinical outcome measures, including motor function, muscle strength and timed‐function tests, were evaluated in 21 adults with BMD at baseline and at 9 and 18 months of follow‐up. Results: Proton density fat fraction increased significantly in 10/17 thigh muscles after 9 months, and in all thigh and lower leg muscles after 18 months. The 32‐item Motor Function Measurement (MFM‐32) scale (−1.3%, p = 0.017), North Star Ambulatory Assessment (−1.3 points, p = 0.010) and patient‐reported activity limitations scale (−0.3 logits, p = 0.018) deteriorated significantly after 9 months. The 6‐min walk distance (−28.7 m, p = 0.042), 10‐m walking test (−0.1 m/s, p = 0.032), time to climb four stairs test (−0.03 m/s, p = 0.028) and Biodex peak torque measurements of quadriceps (−4.6 N m, p = 0.014) and hamstrings (−5.0 N m, p = 0.019) additionally deteriorated significantly after 18 months. At this timepoint, domain 1 of the MFM‐32 was the only clinical outcome measure with a large sensitivity to change (standardized response mean 1.15). Discussion: It is concluded that proton density fat fraction imaging of entire thigh muscles is a sensitive outcome measure to track progressive muscle fat replacement in patients with BMD, already after 9 months of follow‐up. Finally, significant changes are reported in a wide range of clinical and patient‐reported outcome measures, of which the MFM‐32 appeared to be the most sensitive to change in adults with BMD. [ABSTRACT FROM AUTHOR]

In postmenopausal osteoporosis, hormonal alteration leads to bone turnover and muscle weakness. Activin typeIIB receptors were revealed to increase bone & muscle mass. This experiment was designed to explore ActRIIB-Fc-ligands administration alone or with swimming-exercise might restore musculoskeletal system homeostasis followed negative effects of estrogen deficiency in ovariectomized rat model. Materials & Methods: Fifty adult female albino rats were divided into 5groups: Group I (control sham rats) were subjected to i.p. PBS. In the other groups rats were exposed to ovariectomy procedures. Group II, III, IV rats were exposed to i.p. PBS, exercise-training-protocol, i.p. ActRIIB-Fc (5mg/kg/week) 7weeks respectively, while groupV rats were exposed to exercise-training-protocol and i.p ActRIIB-Fc. Finally, body weights & muscle strength tests were examined for all animals. After scarification, uterine weights and muscle mass (quadriceps femoris & gastrocnemius) measurements were obtained. Serum biochemical and histopathological parameters were examined; also, RNA was extracted from their right femora to perform genes expression. Results:Exercise-training and ActRIIB-Fc were capable to reverse changes of muscle strength and bone mass measurements of OVX rats. Significant elevation in osteocalcin & P1NP and significant reduction in CTX, TOS, TAC, IL-1ß, IL-6, and CK values, moreover, down-regulation of RANKL and up-regulation of OPG genes expression were detected. These significant values and histomorphometric osteoporotic variations were more pronounced in groupV. Conclusion:Addition of ActRIIB-Fc ligand to exercise-training-protocol act as a musculoskeletal-enhancing agent in OVX rats. These results were proved by reduction of osteoclast function and elevation of some osteoblast genes expression; therefore, it could be a respectable choice in musculoskeletal disorders management. [ABSTRACT FROM AUTHOR]

Objective: The Posterior Standing Overhead Arm Reach (SOAR) test has been previously reported as a reliable clinical measure of closed chain hip extension motion. The proposed Medial SOAR test expands on that testing approach to provide a similar measure of functional hip adduction motion. This was a preliminary intrarater and interrater reliability and validity study of the Medial SOAR test as a measure of functional hip adduction. Design: Cross-sectional. Setting: University motion analysis laboratory. Participants: Fifty hips were assessed in 25 (22 female) asymptomatic participants (mean age = 23.4 years, SD = 0.8). Main measures: Maximum hip adduction during the Medial SOAR test was measured with a standard goniometer independently by two examiners. The test was also performed using three-dimensional motion capture. The intrarater and interrater reliability of the goniometric measure was determined using intraclass correlation coefficients, and the relationship between measures obtained via goniometry and three-dimensional motion capture was assessed with Pearson correlations and Bland–Altman analysis. Results: Intrarater reliability (ICC2,3) was 0.88 (95% CI = 0.80–0.92) for Examiner 1 and 0.87 (95% CI = 0.79–0.92) for Examiner 2. The standard error of measurement and minimal detectable change were less than 3.0°. Interrater reliability demonstrated an intraclass correlation coefficient = 0.62 (95% CI = 0.28–0.79). Pearson correlations were significant with low-to-moderate associations (r = 0.49, P < 0.001; r = 0.24, P = 0.045). Conclusions: Similar to the previously reported Posterior SOAR test, the Medial SOAR test demonstrated acceptable intrarater and interrater reliability, along with low-to-moderate associations with three-dimensional motion capture. The Medial SOAR test has the potential to provide a reliable and accurate assessment of closed chain hip adduction. [ABSTRACT FROM AUTHOR]

Isokinetics is a proven method to train and objectively assess the capability of muscle groups, particularly at the knee. The current re-injury rates and less than optimal return to sport percentages seen following anterior cruciate ligament surgery highlights the need for greater focus on what tests and methods are used to make these critical decisions. Isokinetics remains the best single method to objectively determine dynamic muscle strength, power, rate of force development and endurance. These factors make it well-suited to play a crucial role in influencing the appropriate patient progression through a rehabilitation program and assisting in determining return to play readiness following injury or surgery. In this article we will discuss why we believe isokinetics is a useful and necessary testing method, and elucidate testing parameters and goals used during knee extension/flexion assessment. [ABSTRACT FROM AUTHOR]

This study compared handheld dynamometry (HHD) at the weakest point of the strength curve for hip extensors, hip abductors, and knee extensors in older adults and onerepetition maximum (1RM) of that same muscle groups with cuff weights. Fifty participants (62-94 years) were tested. Paired t tests indicated no significant differences between the 2 measures. Reliability testing for absolute agreement between 1RM and HHD yielded intraclass correlations of good to excellent. This demonstrates HHD at or near the weakest point of a muscle group provides an accurate measure of older individual's 1RM for knee extension, hip extension, and hip abduction. [ABSTRACT FROM AUTHOR]

Breast cancer is the most common cancer in women worldwide, and its treatment usually involves a combination of many medical procedures, including surgery, chemotherapy, radiotherapy, and hormonal therapy. One of the detrimental effects on physical function is reduced upper limb muscle strength. This study aimed to evaluate upper body strength intra-day and inter-day (test-retest) reliability using the handgrip strength test (HGS) and the bilateral isometric bench press (BIBP) and the test-retest reliability of the one repetition maximum on the bench press (BP-1RM) in breast cancer survivors (BCS). Thirty-two (52.94 ± 8.99 yrs) BCS participated in this study. The muscle strength tests were performed in two different moments, three to seven days apart. Intraclass coefficient correlation (ICC) and coefficient of variation (CV) were used to assess the reliability. Standard error of measurement (SEM), typical error of measurement (TEM), and minimally detectable change (MDC) analyses were performed. The Bland-Altman analysis was used to assess the agreement between test-retest. We found a reliability that can be described as "high" to "very high" (ICC ≥ 0.88; CV ≤ 10%) for intra-day and test-retest. SEM% and MDC% were lower than 5% and 11%, respectively, for all intra-day testing. SEM% and TEM% ranged from 3% to 11%, and MDC% ranged from 9% to 23% in the test-retest reliability. The agreement demonstrated a systematic bias ranging from 2.3% to 6.0% for all testing, and a lower systematic bias may be presented in the non-treated side assessed by HGS and BIBP. HGS, BIBP, and BP-1RM assessments are reliable for measuring upper-body muscle strength in BCS. [ABSTRACT FROM AUTHOR]

Background: Surface electromyography (sEMG) represents a widely utilized technique in medical research. The voluntary response index (VRI) introduces a novel method for analyzing the motor control of voluntary movements via sEMG. This study aimed to assess the reliability of VRI and breakpoint angles (BPA) among professional football players during the Nordic Hamstring test (NHT). Methods: This study included 24 healthy professional football players. Through the use of sEMG, two aspects of VRI [magnitude (MAG) and similarity index (SI)] were evaluated during the NHT. Additionally, BPAs were determined by capturing slow-motion videos of functional tasks. The test-retest reliability across three trials was determined using the intra-class correlation coefficient (ICC). Results: The reliability of the VRI components during the NHT was found to be excellent. The ICC for MAG was 0.9 and 0.81 for the SI. Breakpoint angles exhibited moderate reliability (ICC = 0.65) during a functional task. The SI displayed a lower standard error of measurement (SEM = 0.07). The MAG’s SEM was 0.25, while BPA’s SEM was 17.8. Conclusions: The analysis of the VRI via sEMG showed nearly perfect reliability in professional football players during the NHT, a functional task. Breakpoint angles demonstrated significant reliability. The findings of this study indicate that both VRI and BPA are reliable methods for estimating motor control during dynamic movement tasks in professional athletes. [ABSTRACT FROM AUTHOR]

The purpose of the study was to analyze the test–retest reliability of an isometric and isometric/vibratory muscular strength protocol in the bilateral seated bench press (BSBP), bilateral seated rowing (BSR), unilateral seated right knee extension (USKER), and left knee extension (USKEL) tests controlled using functional electromechanical dynamometry (FEMD) in healthy young adults. A repeated measures design was used to determine the reliability of a muscular strength protocol in isometric and isometric vibration modes with FEMD. No significant differences were found in test–retest analysis (p > 0.05; ES < 0.20); and high reliability (CV = 4.65–5.02%; ICC = 0.99–0.98) was found for BSBP measures, and acceptable reliability (CV = 3.71–9.61%; ICC = 0.98–0.95) was found for BSR, USKER, and USKEL. Furthermore, the coefficients between the two measures were strong (r = 0.963–0.839) and highly significant (p = 0.001) for maximal strength in the isometric and maximal isometric/vibratory assessment of muscle strength in all muscle strength tests. This study demonstrates that isometric and maximal isometric/vibratory strength in the BSBP, BSR, USKER, and USKEL tests can be measured with high reliability and reproducibility using the FEMD. [ABSTRACT FROM AUTHOR]

An accurate trunk muscle strength assessment seems very important to design and individualize training and rehabilitation programs in clinical and sport settings. Hand-held dynamometers (HHDs) are interesting alternatives to isokinetic dynamometers for assessing trunk isometric muscle strength because they are inexpensive instruments and easy to use. This cross-sectional observational study aimed to examine the reliability of two novel sitting tests for assessing trunk flexion and extension isometric strength using an HHD and their relationship with two other novel isometric tests that use an isokinetic dynamometer. Twenty-four female amateur athletes (age: 24.5 ± 2.64 years; body height: 164.45 ± 6.33 cm; body mass: 63.17 ± 10.35 kg) participated in this study. A test-retest design was carried out one-week apart to examine the reliability. The relationship and the degree of agreement between the HHD and the isokinetic dynamometer measurements were analysed using Pearson correlation and Bland-Altman analysis, respectively. In general, the reliability of all isometric strength tests was good, with ICCs ranging from 0.65 to 0.87 and typical error < 15%. Pearson correlations were moderate, with values of r = 0.47 (R² = 0.22) and r = 0.42 (R² = 0.18) for flexion and extension strength, respectively. Bland-Altman plots showed no agreement between HHDs and isokinetic measurements. All trunk isometric tests using both, an isokinetic dynamometer and HHDs, provide reliable measurements for assessing trunk flexion and extension strength. According to the comparative analysis, both measurement types are different and cannot be used interchangeably. Health and sport professionals should choose the test that best suits the biomechanical characteristics required for functional goals or success in a given sport. [ABSTRACT FROM AUTHOR]

Purpose: The present study aimed to investigate a) the associations between bilateral performance utilizing countermovement jump (CMJ), squat jump (SJ), speed and unilateral CMJ, isokinetic peak torque in knee extension and flexion with angular velocities of 60°/s and 180°/s and tensiomyography (TMG) parameters; b) whether the asymmetries derived from unilateral tests are associated with bilateral CMJ, SJ and speed in elite female soccer players. Methods: Thirty-five elite female soccer players (average age: 20 ± 5 years) completed CMJ, SJ, speed, isokinetic muscle strength and TMG tests. Results: Compared to the non-dominant leg, the dominant leg demonstrated greater peak torque output in both knee flexion (7.4%) and knee extension (5.6%) isokinetic tasks, as well as m. vastus medialis contraction time (7.6%), and soccerspecific agility test (4.1%). Conversely, the hamstring to quadriceps peak torque ratio at 180°/s (8.5%) was significantly greater in the non-dominant leg. The associations between CMJ, SJ and speed performance were positive and ranged from weak (r = 0.350) to high (r = 0.710). For speed and TMG-derived variables, correlations were negative and ranged from weak (r = −0.345, p = 0.042, for vastus medialis contraction time) to moderate (r = −0.530, p = 0.001, for biceps femoris contraction time). Furthermore, both bilateral CMJ and SJ negatively correlated with TMG-derived variables, ranging from weak (r = −0.350, p = 0.039, for vastus lateralis contraction time) to moderate (r = −0.537, p = 0.003, for rectus femoris contraction time). Conclusion: The overall significant, albeit inconsistent, correlations between the diverse performance scores obtained highlight the necessity for a multifaceted and thorough diagnostic strategy in female soccer players. [ABSTRACT FROM AUTHOR]

Background: The diaphragm muscle constitutes the internal component of the Lumbo-Pelvic-Hip Complex (LPHC), and its stability is suggested to influence lower limb joint function, particularly the alignment of the patellofemoral joint and the tracking path mechanism of the patella. Objectives: To compare the endurance of the LPHC and diaphragm contractility in females with patellofemoral pain syndrome (PFPS) and a healthy control group. Methods: Fifty-six females, including twenty-eight diagnosed with patellofemoral pain syndrome and twenty-eight healthy females matched as controls (aged 15 - 45), were invited to participate in this case-control study. Endurance scores of trunk extensor, flexor, and lateral flexor muscles, endurance ratios, and the percentage of diaphragm muscle contractility using the ultrasonography method were compared between the two groups. Results: The endurance time of trunk flexors and right and left lateral muscle groups in the PFPS group significantly differed compared to the control group (P < 0.05). Diaphragm contractility in both the right (Mean ± SD: 21.82 ± 3.61; P < 0.001) and left (Mean ± SD: 22.92 ± 2.99; P = 0.007) sides was significantly lower in the PFPS group compared to the control group. Conclusions: Lumbo-Pelvic-Hip Complex stability and diaphragm respiratory function and contractility were impaired in females with PFPS. [ABSTRACT FROM AUTHOR]

Context: The incidence of low back pain (LBP) is high among high school male soft tennis players. In some sports for which the rotational component of the body is important, an association between restricted hip internal rotation of the nondominant leg and LBP has been reported; however, whether this association holds in soft tennis is unknown. Therefore, this study aimed to evaluate the association between hip internal rotation, hip external rotation, hamstring flexibility, iliopsoas flexibility, and LBP incidence. Design: This study was designed as a cross-sectional study, conducted at a sports training center. Methods: Participants comprised 113 male elite high school soft tennis players (age: 16.1 [0.7] y) from 9 elite-level teams. The main outcome measures were the hip internal and external rotation range of motion, hamstring flexibility on the straight leg raise test, and iliopsoas flexibility on the Thomas test. Multiple logistic regression analysis was performed to examine the influence of main outcomes on LBP incidence in the past 1 year. Results: A total of 35 participants had LBP (LBP group); 78 participants did not have LBP (non-LBP group). Multiple logistic regression analysis revealed that the odds ratio for height was 1.08 (95% confidence interval, 1.00–1.16; P =.043) and for the hip internal rotation range of motion in the nondominant leg was 0.90 (95% confidence interval, 0.85–0.95; P <.001), indicating significant associations with LBP. Conclusion: Hip internal rotation range of motion in the nondominant leg and height were crucial factors related to LBP in male elite high school soft tennis players. [ABSTRACT FROM AUTHOR]

Context: Intrasession reliabilities of isometric knee extension kinetics via portable strain gauge have been reported across several knee joint angles and constraints. However, intersession variabilities, which are more valuable, have yet to be determined. Therefore, we aimed to quantify the intersession variability of knee extension kinetics over 3 testing sessions using an affordable and portable strain gauge. Design: Participants performed maximum voluntary isometric contractions of the knee extensors over 3 sessions. Methods: Eleven (6 men and 5 women; 31 [6.4] y) volunteers performed maximum voluntary isometric contractions in constrained (isokinetic setup with thigh and chest straps) and unconstrained (treatment plinth) conditions. Peak force (PF), peak rate of force development, rate of force development (RFD), and impulse (IMP) from 20% to 80% of PF were assessed. Means, SDs, percentage changes, minimal detectable changes, coefficients of variation (CV), and intraclass correlation coefficients (ICC) were calculated and reported. Results: PF had the lowest intersession variability regardless of condition (CV = 5.5%–13.8%, ICC =.67–.93). However, variability of peak rate of force development (CV [range] = 12.2%–24.7%, ICC =.50–.78), RFD (CV = 10.0%–26.8%, ICC =.48–.84), and IMP (CV = 15.2%–35.4%, ICC =.44–.88) was moderate at best. The constrained condition (CV [SD] = 14.1% [4.8%], ICC =.74 [.08]) had lower variability compared with the plinth (CV = 19.8% [7.9%], ICC =.68 [.15]). Variability improved from sessions 1 to 2 (CV = 20.4% [7.7%], ICC =.64 [.14]) and to sessions 2 to 3 (CV = 15.3% [6.4%], ICC =.76 [.10]). Conclusions: PF can be assessed regardless of setup. However, RFD and IMP changes across sessions should be approached with caution. Backrests and thigh straps improve RFD and IMP variability, and at least 1 familiarization session should be provided before relying on knee-extensor kinetics while utilizing a portable strain gauge. [ABSTRACT FROM AUTHOR]

Background: The relationship between hamstring strength and hop performance after anterior cruciate ligament (ACL) reconstruction with hamstring tendon (HT) autografts has not been well elucidated. The aim was to investigate the relationship between eccentric hamstring strength, assessed with the NordBord, and concentric hamstring strength, assessed with the Biodex, with hop performance at 8 and 12 months after ACL reconstruction. Methods: Registry study. Patients ≥ 16 years who had undergone primary ACL reconstruction with HT autograft, followed by muscle strength and hop tests at 8 and 12 months were included. Correlations of the relative hamstring strength (Nm/kg or N/kg) and limb symmetry index (LSI) with hop performance were analyzed. Pearson's correlation coefficient, and coefficient of determination (r2) were used for statistical analysis. Results: A total of 90 patients were included, of which 48 (53%) were women. The mean age at ACL reconstruction was 27.0 ± 8.0 years. Relative hamstring strength had significant positive correlations with hop performance, ranging from r = 0.25–0.66, whereas hamstring strength LSI had significant positive correlations which ranged from r = 0.22–0.37 at 8 and 12 months after ACL reconstruction. At 12 months, the relative hamstring strength in the Biodex explained 32.5–43.6% of the hop performance in vertical hop height, hop for distance relative to height, and the total number of side hops, whereas the relative hamstring strength in the NordBord explained 15.2–23.0% of the hop performance. Conclusion: The relative hamstring strength in the Biodex test explained 32.5–43.6% of the hop performance, whereas the relative hamstring strength in the NordBord explained 15.2–23.0%. Thus, our findings suggest that relative hamstring strength, especially in the hip-flexed position may be a better indicator of hop performance at 8 and 12 months after ACL reconstruction in patients treated with HT autograft. [ABSTRACT FROM AUTHOR]