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Keywords: Instrumented treadmill; MEMS gyroscope; gait analysis; running patterns; foot strike EN Instrumented treadmill MEMS gyroscope gait analysis running patterns foot strike S484 S486 3 01/29/21 20191002 NES 191002 1. Instrumented treadmill, MEMS gyroscope, gait analysis, running patterns, foot strike. [Extracted from the article]

Keywords: Instrumented treadmill; MEMS gyroscope; gait analysis; power spectrum density; harmonic analysis EN Instrumented treadmill MEMS gyroscope gait analysis power spectrum density harmonic analysis S343 S344 2 01/29/21 20191002 NES 191002 1. Instrumented treadmill, MEMS gyroscope, gait analysis, power spectrum density, harmonic analysis. [Extracted from the article]

Background Lower limbs muscle flexibility remains a common assessment in sports therapy. Nevertheless no clear consensus exists about the methods for performing reliable measurements. Objective The aim of the present study was to examine the reliability of muscle flexibility measures in adolescent athletes. Design Randomised test-retest study. Setting Sports academy physiotherapy laboratory. Participants Height young athletes (age: 15.1±1.6, body mass: 65.4±26.2 kg, height: 171.7±8.8 cm) training in a national sports centre. Interventions Flexibility of the main lower limb muscles was assessed, using a standardised force of stretching for each muscle and a video analysis software for measuring the angles. Each participant was tested on both sides by three operators and on two separate occasions, 4 days apart. Final measurements were reported in degrees. Main outcome measurements Reliability of flexibility measures was assessed by 1) calculating the between-day difference expressed as Cohen's d (90% CI), no substantial difference was considered if Cohen's d<0.2 and the 90% CI included zero, and 2) the typical error of measurement, expressed as a coefficient of variation (CV, 90% CI). Results Force of stretching (in N), mean angle (SD), mean between-day difference and CV were 78.5, 132.2 (10.1), −0.05 (−0.3;0.2) and 8.3% (7.5;9.3) for quadriceps, 68.7, 70 (11.2), −0.7 (−1.7;0.4) and 3.3% (3.0;3.7) for hamstrings, 39.2, 53.5 (9.4), 0.05 (−0.2;0.3) and 7.2% (6.5–8.0) for adductors, 147.2, 16 (6.3), 0.10 (−0.1;0.3) and 5.7% (5.1;6.3) for gastrocnemius, 147.2, 30.6 (8.9), 0.01 (−0.2;0.2) and 4.5% (4.0;5.0) for soleus, 98.1, 22.7 (5.9), 0.01 (−0.2;0.2) and 2.6% (2.3;2.9) for hip flexors, 49.1, 54.7 (14.5), −0.04 (−0.2;0.2) and 9.6% (8.6;10.8) for hip medial rotator and 49.1, 43.5 (14.9), −0.08 (−0.3;0.1) and 18.2% (16.3;20.5) for hip lateral rotator. Conclusion The present method for assessing lower limb muscles flexibility has a moderate-to-good level reliability and may integrate prevention programs. [ABSTRACT FROM PUBLISHER]

CONTEXT: Chronic ankle instability (CAI) is the most serious long-term complication following an ankle sprain. Taping and bracing are frequently employed in the return to sport (RTS) continuum to avoid injury recurrence and to maximize post-injury performance. The Ankle-GO score is a valid and reliable objective RTS criteria, but the influence of ankle supports on this score in CAI patients remains unknown.OBJECTIVES: We aimed to evaluate the induce effects of taping or bracing on the Ankle-GO score among patients suffering from CAI.DESIGN: Crossover StudySETTING: Sports medicine research laboratoryPATIENTS: Thirty CAI patients (13 males and 17 females, 33.4 ±11.7 years) performed the Ankle-GO score in three conditions (taping, bracing and no ankle support).MAIN OUTCOME MEASURES: The Ankle-GO is a 25-point score clustering 2 self-reported questionnaires (Foot and Ankle Ability Measure and Ankle Ligament Reconstruction-Return to Sport after Injury) and 4 functional tests (Single Leg Stance, Star Excursion Balance Test, Side Hop Test and Figure-of-eight test). Performances on each component as well as the total score were compared between conditions using repeated measures of ANOVA.RESULTS: Taping and bracing significantly and equally improved the Ankle-GO score compared with no support (12.8 ±5.3 and 11.2 ±4.2 vs. 8 ±4.5 points respectively, P<.001). However, significant improvements were found solely in self-reported questionnaires with ankle support (P<.001). No differences were found in functional tests, although both taping and bracing significantly lowered instability perception during the tests (+1.9 and +1.8 points, respectively).CONCLUSION: Ankle-GO scores were significantly enhanced with taping or bracing. However, only self-reported function and psychological readiness were improved. Functional performance was not altered, although external supports enhanced perceived stability. Both taping and bracing supports appear equally important in improving self-confidence and perceived ankle stability among individuals with CAI returning to sport., Competing Interests: Competing interests and financial disclosure: none

Context: Chronic ankle instability (CAI) is prevalent among individuals who sustain a lateral ankle sprain (LAS) injury. The persistence of the characteristic long-standing clinical symptoms of CAI may be attributable to the lack of adoption by physiotherapists of evidence-informed clinical guidelines., Objective: To investigate the extent to which French-speaking physiotherapists implement the International Ankle Consortium rehabilitation-oriented assessment (ROAST) framework when providing clinical care for individuals with an acute LAS injury., Design: Cross-sectional study., Setting: Online survey informed by a Delphi process of foot-ankle experts., Patients or Other Participants: A total of 426 French-speaking physiotherapists completed the online survey., Main Outcome Measure(s): The survey was disseminated to French-speaking physiotherapists in France; Switzerland; Quebec, Canada; Luxembourg; and Belgium. It comprised closed and open-ended questions organized in 5 sections: (1) participant demographics, (2) participant self-assessment of expertise, (3) clinical diagnostic assessment of the ankle (bones and ligaments), (4) clinical evaluation after an acute LAS injury (ROAST framework), and (5) CAI. The qualitative data from the open-ended questions were analyzed using best-practice thematic-analysis guidelines., Results: Only 6.3% (n = 27) of the respondents could name all Ottawa Ankle Rules criteria. Only 25.6% (n = 109) of the respondents cited or described criterion standard tests from the literature to assess the integrity of the lateral ankle ligaments. Less than 25% (n = 71) of the respondents reported using clinical evaluation outcome metrics (ROAST) recommended by the International Ankle Consortium to inform their clinical care for individuals with an acute LAS injury. In general, the respondents had a greater knowledge of the functional than the mechanical insufficiencies associated with CAI., Conclusion: A minority of French-speaking physiotherapist survey respondents use the International Ankle Consortium ROAST to inform their clinical care for individuals with an acute LAS injury. This highlights the responsibility of the scientific community to better disseminate evidence-informed research to clinicians., (© by the National Athletic Trainers’ Association, Inc.)

Objective: To evaluate isokinetic dynamometer reliability for isometric assessment of plantar flexor (PF) strength., Design: Cross-sectional., Setting: Testing by the same physiotherapist twice during a first session (repeatability) and once during a second session (reproducibility)., Participants: Twenty-two healthy subjects (44 ankles, 11 men/11 women)., Main Outcome Measures: Isometric PF peak torque, with and without body mass normalization, at 0° and +20° of plantar flexion. Measurement reliability was evaluated using intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC)., Results: Without normalization, measurement repeatability was excellent at 0° of plantar flexion (ICC, 0.94; SEM, 6.6%; MDC, 18.4%) compared with good repeatability at +20° (ICC, 0.85; SEM, 11.1%; MDC 30.6%). Measurement repeatability following normalization was good at 0° (ICC, 0.88; SEM, 5.2%; MDC, 14.4%) and +20° (ICC, 0.79; SEM, 10.2%; MDC, 28.1%). While reproducibility was good at 0° with normalization (ICC, 0.84; SEM, 5.9%; MDC, 16.3%) or excellent without (ICC 0.92; SEM 7.5%; MDC, 20.8%), it was moderate at +20° with normalization (ICC 0.71; SEM 11.3%; MDC, 31.3%) or good without (ICC 0.78; SEM 13.0%; MDC, 36.1%)., Conclusion: The reliability of PF maximal isometric strength is good/excellent at 0° of plantar flexion but moderate/good at +20°., Competing Interests: Declaration of competing interest None declared., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: To analyse the association between Ankle-GO score during the return to sport process and the probability of becoming a coper 1 year after lateral ankle sprain (LAS). Copers were defined as patients returning to their preinjury sport without loss of function and reporting no episodes of reinjury or giving-way., Methods: Two months after a LAS, patients performed the Ankle-GO assessment which includes a cluster of four functional tests and two self-reported questionnaires for a maximum score of 25 points. One year after injury, participants were classified as copers or non-copers. Eight potential predictive variables associated with coper status were compared between the groups. Receiver operating characteristic curves (area under the curve (AUC)) and multivariable logistic regression models with OR and 95% CIs were used to determine the association of potential factors, including the Ankle-GO score, with copers., Results: 64 patients (56% females; age 33.7±13.2 years) completed the Ankle-GO-GO at 2 months postinjury. At 1 year postinjury, 10 patients (15%) were lost to follow-up, and only 17 of 54 patients (31%) became copers. Two-month Ankle-GO score was higher among copers (9.9±4.9 points vs 6.9±3.7, p=0.015) and was associated with future coper status at 1 year (AUC=0.70). Patients with an Ankle-GO score above 11 points and male patients were more likely to become copers (OR=12.1; 95% CI 2.5 to 59, p=0.002 and OR=5.2; 95% CI 1.2 to 22.4, p=0.026, respectively)., Conclusion: The Ankle-GO may help identify patients more likely to become copers within a year of injury. Those with low Ankle-GO scores and female patients should receive additional rehabilitation to increase the odds of becoming a coper., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

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.

The primary objective of this study was to investigate the relationship between metatarsophalangeal joint (MTPj) flexion torque and sprint acceleration, cutting and jumping performance, and kinetics. A secondary aim was to explore this relationship when MTP flexion strength was associated with other foot and lower limb neuromuscular outputs. After an initial MTPj flexion torque assessment using a custom-built dynamometer, 52 high-level athletes performed the following tasks on a force platform system: maximal sprint acceleration, 90-degree cutting, vertical and horizontal jumps, and foot-ankle hops. Their foot posture, foot passive stiffness and foot-ankle reactive strength were assessed using the Foot Posture Index, the Arch Height Index Measurement System and the Foot-Ankle Rebound Jump Test. Ankle plantarflexion and knee extension isometric torque were assessed using an isokinetic dynamometer. During maximal speed sprinting, multiple linear regressions suggested a major contribution of MTPj flexion torque, foot passive stiffness and foot-ankle reactive strength to explain 28% and 35% of the total variance in the effective vertical impulse and contact time. Ankle plantarflexor and quadriceps isometric torques were aggregately contributors of acceleration performance and separate contributors of cutting and jumping performance. In conclusion, MTPj flexion torque was more strongly associated with sprinting performance kinetics especially at high-speed.

Background: Lateral ankle sprain (LAS) is the most common sports injury, leading to a high rate of recurrence and the development of chronic ankle instability. One possible explanation is the lack of objective, evidence-based criteria to inform return to sport decisions following LAS. The aim of this study was therefore to assess the efficacy of a new functional score to distinguish patients at risk of recurrent LAS within two years after the initial injury., Methods: The Ankle-GO score was used in 64 active patients two months after LAS. This composite score includes 2 self-reported questionnaires and 4 functional tests, for a maximum score of 25 points. The rate of reinjury was prospectively recorded 2 years after inclusion. Potential predictive variables for reinjury were tested using the Chi-square and independent t-tests. The area under the receiver operating characteristics curve (AUC) with the optimal cut-off score was determined to assess the predictive value of the Ankle-GO score for the risk of reinjury. Multivariate logistic regression was then used to determine the influence of risk factors of reinjury., Results: Fifty-four (85%) patients were included (23 men and 31 women, 34.7 ± 13 years old) including 18 (33.3%) with a reinjury. The two-month Ankle-GO score was lower in patients with a recurrent LAS (5.4 ± 2.8 points vs. 9.1 ± 4.5, p = 0.002) and predicted the risk of reinjury (AUC = 0.75). Patients with < 8 points were found to have a significantly higher risk of reinjury (OR = 8.6; 95%CI: 2-37.2, p = 0.001). Women also tend to have a higher risk of recurrence (OR = 3.8; 95%CI: 0.9-15.5, p = 0.065)., Conclusion: The Ankle-GO score is a new objective criterion for RTS after LAS. Patients with a low score at two months have a 9-fold greater risk of recurrence within two years., (© 2024. The Author(s).)

Purpose: To evaluate the variations in hip muscles strength following arthroscopy and 6-month rehabilitation in patients treated for femoroacetabular impingement (FAI)., Methods: A retrospective analysis was carried out on a series of patients who were arthroscopically treated for FAI at La Tour Hospital between 2020 and 2022. Bilateral isometric strengths of 8 hip-related muscles (abductors, adductors, hamstrings, quadriceps, extensors, flexors, internal and external rotators) were assessed using a handheld dynamometer before surgery and postoperatively after 6 months of rehabilitation in terms of relative strength changes between time points., Results: A total of 29 patients (aged 26.9 ± 7.1 years, 86% of women) were included. Except for the abductors, which remained of comparable strength than before surgery, a statistically significant ( P < .05) increase in hip muscle strength on the operated side could be noted at 6 postoperative months for hamstrings (9% ± 17%, P  = .041), quadriceps (11% ± 27%, P  = .045), extensors (17% ± 32%, P  = .006), flexors (17% ± 29%, P  = .003), adductors (18% ± 23%, P < .001), and internal rotators (32% ± 36%, P < .001). The proportion of patients who reached a strength level above their preoperative status ranged from 62% (quadriceps) to 86% (adductors and flexors), depending on the muscle studied. The external rotators were the only muscles that remained significantly weakened at 6 months on both operated (-13% ± 26%, P  = .002) and nonoperated (-17% ± 25%, P < .001) sides, with a decrease beyond 15% in almost half of the patients (45% and 48%, respectively)., Conclusions: Arthroscopic treatment followed by 6-month rehabilitation granted to most FAI patients a higher strength level for several hip muscles, except for abductors and external rotators, which remained comparable and weakened, respectively., Level of Evidence: Level IV, therapeutic case series., Competing Interests: The authors report no conflicts of interest in the authorship and publication of this article. Full ICMJE author disclosure forms are available for this article online, as supplementary material., (© 2024 The Authors.)

Purpose: To provide normative values of maximal isometric torque of knee extensors and flexors measured at 80° of knee flexion and to characterize the results in healthy subjects practicing activities at risk of anterior cruciate ligament rupture., Methods: Seventy-four trained volunteers (35 male and 39 female) aged 18 to 41 years were recruited. They alternately performed 3 maximal voluntary isometric contractions of knee extension and flexion. The maximal voluntary isometric contraction net torque was computed as the mean value of the peak torques recorded over the 3 trials., Results: For women, the absolute torque for extensors was 143.5 ± 34.4 N⋅m (range, 87.7-253.1 N⋅m) and 66.8 ± 13.8 N⋅m (range, 37.5-93.1) for flexors. For men, the absolute torque for extensors was 199.8 ± 47.3 N⋅m (range, 99.3-311.5 N⋅m) and 89.8 ± 21.0 N⋅m (range, 51.8-137.2 N⋅m) for flexors. For women, the body mass normalized torque for extensors was 2.20 ± 0.51 N⋅m.kg -1 (range, 1.22-3.74 N⋅m.kg -1 ) and 1.04 ± 0.26 N⋅m.kg -1 (range, 0.41-1.50 N⋅m.kg -1 ) for flexors. For men, the normalized torque for extensors was 2.74 ± 0.58 N⋅m.kg -1 (range, 1.51-4.08 N⋅m.kg -1 ) and 1.24 ± 0.30 N⋅m.kg -1 (range, 0.64-2.05 N⋅m.kg -1 ) for flexors., Conclusions: This study provides absolute and normalized normative values of maximal isometric torque measured at 80° of knee flexion for extensors and flexors in a series of healthy trained subjects practicing activities at risk of anterior cruciate ligament rupture. The considerable level of interlimb asymmetry and the weak association between dominance and strength observed in uninjured subjects call into question the classical use of contralateral side as reference for injured patients., Clinical Relevance: Patients with anterior cruciate ligament (ACL) injuries are the most represented subjects using isokinetic dynamometers in many sport medicine and rehabilitation departments. Clinicians need reference values to compare patients with ACL injuries with comparable healthy subjects. This study may provide this information., Competing Interests: The authors report the following potential conflicts of interest or sources of funding: This study was funded by French-speaking Arthroscopy Society (SFA) and Physioswiss. All authors (S.B.B., M.-A.D., A.W., A.D., F.F., H.B.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Full ICMJE author disclosure forms are available for this article online, as supplementary material., (© 2023 The Authors.)

Background: Lateral ankle sprain (LAS) is the most common sports-related injury. However, there are currently no published evidence-based criteria to guide the patient's return to sport (RTS) and this decision is generally time-based. The aim of this study was to assess the psychometric properties of a new score (Ankle-GO) and its predictive ability for RTS at the same level of play after LAS., Hypothesis: The Ankle-GO is robust for discriminating and predicting RTS outcomes., Study Design: Prospective diagnostic study., Level of Evidence: Level 2., Methods: The Ankle-GO was administered to 30 healthy participants and 64 patients at 2 and 4 months after LAS. The score was calculated as the sum of 6 tests for a maximum of 25 points. Construct validity, internal consistency, discriminant validity, and test-retest reliability were used to validate the score. The predictive value for the RTS was also validated based on the receiver operating characteristic (ROC) curve., Results: The internal consistency of the score was good (Cronbach's alpha coefficient of 0.79) with no ceiling or floor effect. Test-retest reliability was excellent (intraclass coefficient correlation = 0.99) with a minimum detectable change of 1.2 points. The 2-month scores were significantly lower than 4-month and control group scores (7.7 ± 4, 13.9 ± 4.6, and 19.6 ± 3.4 points, respectively, P < 0.01). Ankle-GO values were also significantly higher in patients who returned to their preinjury level at 4 months compared with those who did not ( P < 0.01). The predictive value of the 2-month Ankle-GO score was fair for a RTS at the same or higher than preinjury level at 4 months (area under ROC curve, 0.77; 95% CI, 0.65-0.89; P < 0.01)., Conclusion: The Ankle-GO appears to be a valid and robust score for clinicians to predict and discriminate RTS in patients after LAS., Clinical Relevance: Ankle-GO is the first objective score to help in the decision-making of the RTS after LAS. At 2 months, patients with an Ankle-GO score <8 points are unlikely to RTS at the same preinjury level., Competing Interests: The following authors declared potential conflicts of interest: R.L. has received royalties from Serf Extremity, PODONOV, and Implant Service Orthopedie, and consulting fees and honoraria from Arthrex. A.H. has received consulting fees from Arthrex.

Static measurements are clinically useful in characterising foot morphology, but it remains unclear to what extent it can influence dynamic lower limb performance. Therefore, the purpose of this study was to investigate if foot posture or foot morphology deformation relates to ankle plantarflexion isokinetic strength and specific kinetics variables during jumping using principal component analysis (PCA). Thirty-eight physically active participants performed drop vertical jump (DVJ) onto force platforms and ankle plantarflexion contractions in different modalities on an isokinetic dynamometer. Foot posture was assessed using the Foot Posture Index-6 item, whereas foot one-, two- and three-dimensional morphological deformation was calculated using the Arch Height Index Measurement System. A PCA was applied to the ankle plantarflexion and kinetics performance data and correlations between PCs and foot parameters measured. The analysis revealed 3 PCs within the ankle plantarflexion and DVJ kinetics variables that captured more than 80% of the variability within the data, but none of them showed significant correlations ( r  ≤ 0.27) with any foot variables. While foot posture and foot morphological deformation remain of interest in characterising foot morphology across individuals, these findings highlight the lack of clinical relevance of these static evaluations at characterising lower limb and ankle performance.

Context: Mounting evidence suggests neuromuscular electrical stimulation (NMES) as a promising modality for enhancing lower limb muscle strength, yet the functional effects of a single electrical stimulation session for improving the function of the intrinsic foot muscles (IFM) has not been evaluated., Objective: To investigate the immediate effects of an NMES session compared with a sham stimulation session on foot force production, foot dome stability, and dynamic postural control in participants with static foot pronation., Design: Randomized controlled clinical trial., Setting: Laboratory., Patients or Other Participants: A total of 46 participants (23 males, 23 females) with static foot pronation according to their Foot Posture Index (score ≥ 6) were randomly assigned to an NMES (n = 23) or control (n = 23) group., Intervention(s): The NMES group received a single 15-minute NMES session on the dominant foot across the IFM. The control group received a 15-minute sham electrical stimulation session., Main Outcome Measure(s): All outcome measurements were assessed before and after the intervention and consisted of foot force production on a pressure platform, foot dome stability, and dynamic postural control. Statistical analysis was based on the responsiveness of the outcome measures and responder analysis using the minimum detectable change scores for each outcome measure., Results: In the NMES group, 78% of participants were classified as responders for at least 2 of the 3 outcomes, compared with only 22% in the control group. The relative risk of being a responder in the NMES group compared with the control group was 3.6 (95% CI = 1.6, 8.1]. Interestingly, we found that all participants who concomitantly responded to foot strength and navicular drop (n = 8) were also responders in dynamic postural control., Conclusions: Compared with a sham stimulation session, a single NMES session was effective in immediately improving foot function and dynamic postural control in participants with static foot pronation. These findings support the role of NMES for improving IFM function in this population., (© by the National Athletic Trainers' Association, Inc.)

Hip arthroscopy and surgical hip dislocation (SHD) can be adequate surgical options for patients suffering from femoroacetabular impingement (FAI) syndrome, but there is to date no published data on their impact on hip muscles strength. The purpose of this retrospective study was, therefore, to evaluate it on a consecutive series of 50 FAI patients treated either by arthroscopy (n = 29, aged 27.4 ± 7.5 years, 76% of women) or SHD (n = 21, aged 25.9 ± 6.5 years, 38% of women) at La Tour Hospital between 2020 and 2021. The bilateral isometric strengths of eight hip-related muscles were evaluated before and three months after surgery (halfway through the rehabilitation program). For arthroscopy, a statistically significant (p < 0.05) reduction in hip muscles strength could be noted on the operated hamstrings (1.49 ± 0.43 vs. 1.39 ± 0.38 Nm/kg), flexors (1.88 ± 0.46 vs. 1.73 ± 0.41 Nm/kg), abductors (1.97 ± 0.42 vs. 1.72 ± 0.40 Nm/kg) and external rotators (1.17 ± 0.40 vs. 1.04 ± 0.37 Nm/kg). The abductors were the most affected muscles, with 45% of the patients suffering from a strength reduction ≥15%. The non-operated external rotators were also affected but to a lesser extent (1.21 ± 0.38 vs. 1.10 ± 0.36 Nm/kg). For SHD, a statistically significant strength reduction could be noted on the operated extensors (2.28 ± 0.84 vs. 2.05 ± 0.70 Nm/kg), abductors (1.87 ± 0.49 vs. 1.65 ± 0.41 Nm/kg), quadriceps (2.96 ± 0.92 vs. 2.44 ± 0.89 Nm/kg), external rotators (1.16 ± 0.42 vs. 0.93 ± 0.36 Nm/kg) and internal rotators (1.26 ± 0.38 vs. 0.96 ± 0.30 Nm/kg). The internal rotators were the most affected muscles, with 75% of the patients suffering from a strength reduction ≥15%. To conclude, particular attention should be paid to operated abductors for patients treated by arthroscopy as well as operated internal/external rotators, abductors and quadriceps for those treated by surgical hip dislocation. It reinforces that a rehabilitation method based on isolated muscle reinforcement and functional exercises that goes beyond three postoperative months is needed.

Currently, there is no consensus on the best rehabilitation program to perform for nonspecific chronic low back pain (NSCLBP). However, multimodal exercises, education, and group-based sessions seem to be beneficial. We, therefore, launched such a treatment program and aimed to evaluate its effectiveness in improving patient health status. We retrospectively analyzed the records of 23 NSCLB patients who followed the MyBack program at La Tour hospital from 2020 to 2022 (25 sessions, 8 weeks). Patients were evaluated before and after intervention using pain on a visual analog scale (pVAS), Roland−Morris Disability Questionnaire (RMDQ), Pain Catastrophizing Scale (PCS), Tampa Scale of Kinesiophobia (TSK), and the EuroQol-5D-3L (EQ-5D-3L). Responder rates were calculated using minimal clinically important differences. Patients reported a significant reduction (p < 0.05) in the pVAS (5.3 ± 1.2 vs. 3.1 ± 1.6), RMDQ (8.8 ± 3.3 vs. 4.0 ± 3.7), PCS (24.5 ± 9.4 vs. 11.7 ± 7.9) and TSK (41.5 ± 9.2 vs. 32.7 ± 7.0). The EQ-5D-3L also statistically improved (score: 0.59 ± 0.14 vs. 0.73 ± 0.07; and VAS: 54.8 ± 16.8 vs. 67.0 ± 15.2). The responder rates were 78% for the pVAS and PCS, 74% for the RMDQ and TSK, and only 26% for the EQ-5D-3L. The MyBack program combining education with multimodal group exercises led to satisfactory clinical, functional, and psychosocial outcomes.

In sports medicine and rehabilitation of musculoskeletal conditions, training, knowledge and expertise of clinicians are the guarantors of good clinical practice. But are they really? Since the 1970s, a growing body of sociological and behavioral science has developed the concepts of cognitive biases and thinking errors. In a nutshell, it tries to explain how we approach decision-making using shortcuts, or heuristics. Our brains will alternatively use 2 systems to think and decide: system 1 is fast, intuitive and emotional, whereas system 2 is slow, logical and conscious. We may think clinicians use the latter systematically, but they actually use system 1 in many situations. Whether due to intrinsic thinking errors or external forces that cloud our judgment, we are under unconscious influences and so are all the stakeholders in the rehabilitation setting, including the patient/athlete. We present some of the most prevalent biases that pervade clinical decision-making and attempt to give a bit of background context starting from the typical tension between academic authority and personal experience. The field of sports performance is also riddled with beliefs, egocentrism and a general tendency to search for magic bullets that will bring the marginal gains and edge over the competition. This plays into the rehabilitation of patient-athletes in different ways. Finally, there are ways to mitigate the effect of cognitive biases to improve decision-making. This must include better communication, shared decisions and ultimately the understanding that we should drive our profession to deliver high-value care tailored to the patients, in line with the best evidence at the best possible cost. Hopefully, we can shed some light without too many of our own biases on the complexities of thinking in sports medicine and rehabilitation., Competing Interests: Conflict of Interest None declared., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Lateral ankle sprain is the most common injury in sports, with up to 40% of patients developing chronic ankle instability (CAI). One possible cause underlying this high rate of recurrence or feeling of giving way may be a premature return to sport (RTS). Indeed, except for time-based parameters, there are no specific criteria to guide clinicians in their RTS decisions in patients with CAI. A recent international consensus highlighted the relevance and importance of including patient-reported ankle function questionnaires combined with functional tests targeting ankle impairments in this population. Thus, the aim of this narrative review and expert opinion was to identify the most relevant functional performance tests and self-reported questionnaires to help clinicians in their RTS decision-making process following recurrent ankle sprains or surgical ankle stabilization. The PubMed (MEDLINE), PEDro, Cochrane Library and ScienceDirect databases were searched to identify published articles. Results showed that the single leg stance test on firm surfaces, the modified version of the star excursion balance test, the side hop test and the figure-of-8 test appeared to be the most relevant functional performance tests to target ankle impairments in patients with CAI. A combination of the Foot and Ankle Ability Measure (FAAM) and the Ankle Ligament Reconstruction-Return to Sport after Injury (ALR-RSI) questionnaires were the most relevant self-reported questionnaires to assess patient function in the context of CAI. Although these functional tests and questionnaires provide a solid foundation for clinicians to validate their RTS decisions in patient with CAI, objective scientific criteria with cut-off scores are still lacking. In addition to the proposed test cluster, an analysis of the context, in particular characteristics related to sports (e.g., fatigue, cognitive constraints), to obtain more information about the patient's risk of recurrent injury could be of added value when making a RTS decision in patients with CAI. In order to evaluate the strength of evertors under ecological conditions, it would also be interesting to assess the ability to control weight-bearing ankle inversion in a unipodal stance. Further studies are needed to assess the relevance of this proposed test cluster in RTS decision-making following lateral ankle sprain injury and CAI., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Picot, Hardy, Terrier, Tassignon, Lopes and Fourchet.)

The purpose of this study was to determine the effect of fatigue on impact shock wave attenuation and assess how human biomechanics relate to shock attenuation during running. In this paper, we propose a new methodology for the analysis of shock events occurring during the proposed experimental procedure. Our approach is based on the Shock Response Spectrum (SRS), which is a frequency-based function that is used to indicate the magnitude of vibration due to a shock or a transient event. Five high level CrossFit athletes who ran at least three times per week and who were free from musculoskeletal injury volunteered to take part in this study. Two Micromachined Microelectromechanical Systems (MEMS) accelerometers (RunScribe®, San Francisco, CA, USA) were used for this experiment. The two RunScribe pods were mounted on top of the foot in the shoelaces. All five athletes performed three maximum intensity runs: the 1st run was performed after a brief warmup with no prior exercise, then the 2nd and the 3rd run were performed in a fatigued state. Prior to the 2nd and the 3rd run, the athletes were asked to perform at maximum intensity for two minutes on an Assault AirBike to tire them. For all five athletes, there was a direct correlation between fatigue and an increase in the aggressiveness of the SRS. We noticed that for all five athletes for the 3rd run the average SRS peaks were significantly higher than for the 1st run and 2nd run (p < 0.01) at the same natural frequency of the athlete. This confirms our hypothesis that fatigue causes a decrease in the shock attenuation capacity of the musculoskeletal system thus potentially involving a higher risk of overuse injury.

Background: Despite being the most commonly incurred sports injury with a high recurrence rate, there are no guidelines to inform return to sport (RTS) decisions following acute lateral ankle sprain injuries. We aimed to develop a list of assessment items to address this gap., Methods: We used a three-round Delphi survey approach to develop consensus of opinion among 155 globally diverse health professionals working in elite field or court sports. This involved surveys that were structured in question format with both closed-response and open-response options. We asked panellists to indicate their agreement about whether or not assessment items should support the RTS decision after an acute lateral ankle sprain injury. The second and third round surveys included quantitative and qualitative feedback from the previous round. We defined a priori consensus being reached at >70% agree or disagree responses., Results: Sixteen assessment items reached consensus to be included in the RTS decision after an acute lateral ankle sprain injury. They were mapped to five domains with 98% panellist agreement-PAASS: P ain (during sport participation and over the last 24 hours), A nkle impairments (range of motion; muscle strength, endurance and power), A thlete perception (perceived ankle confidence/reassurance and stability; psychological readiness), S ensorimotor control (proprioception; dynamic postural control/balance), S port/functional performance (hopping, jumping and agility; sport-specific drills; ability to complete a full training session)., Conclusion: Expert opinion indicated that pain severity, ankle impairments, sensorimotor control, athlete perception/readiness and sport/functional performance should be assessed to inform the RTS decision following an acute lateral ankle sprain injury., Trial Registration Number: ACTRN12619000522112., Competing Interests: Competing interests: KT, TB, OBAO, ED and EV are on the BJSM Editorial Board., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Obese people are often encouraged to lose body mass by exercise. The aim of the study was to determine the effect of body mass and ankle muscle strength on the dynamic foot-pressure distribution before and after running. Twenty-five normal weight (72.0±5.3kg), 25 overweight (80.8±5.6kg) and 25 obese (96.8±6.5kg) age- and height-matched male recreational runners joined the study. Before and after 30min running, dynamic foot-pressure distribution during running, and ankle plantarflexor, dorsiflexor, invertor and evertor muscle strength were measured using a foot-scan pressure-plate and isokinetic dynamometer, respectively. Body mass index and percentage fat mass correlated positively to almost all components of foot-pressure distribution; this explantion was extracted from 14% (for toe 1) to 52% (for dynamic arch index) of peak foot pressure and between 21% (for metatarsal 1) to 48% (for midfoot) of the impulse underneath different foot zones. Only plantarflexor muscle strength significantly predicted plantar pressure and impulse underneath the T1, T2-5, midfoot area and the dynamic arch index. After running, plantarflexor and invertor muscle strength predicted from 30% (for metatarsal 2) to 58% (for metatarsal 1) of peak foot-pressure and impulse underneath the different foot zones. Obesity is associated with excessive plantar loading that is aggravated after running by fatigue-related reductions in plantar flexor and invertor muscle strength. To prevent foot pain and injuries related to excessive foot pressures, at the start of the weight control process non-weight bearing rather than weight-bearing exercise is advisable., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Purpose: Obesity increases the stresses applied to the foot. Ergonomic rocker sole shoes increase energy expenditure of standing and walking in obese individuals but could potentially alter plantar pressure distribution. The aim of this study was to compare plantar pressure distribution during standing and walking between rocker sole and flat-bottomed shoes in obese subjects. Methods: Twenty adult obese women were asked to stand quietly and to walk at their preferred walking speed whilst wearing flat-bottomed or rocker sole shoes. Plantar pressure distribution was assessed using instrumented insoles. Results : During standing, toe pressure and as well as midfoot force were higher with rocker sole than with flat-bottomed shoes ( p  < 0.05). During walking with rocker sole shoes, mean pressure and maximal force were lower under the toes and the forefoot, but higher under the midfoot and rearfoot regions with respect to flat-bottomed shoes ( p  < 0.05). Conclusions : While standing with rocker sole shoes, obese subjects showed augmented pressure under the toes whereas forefoot and heel pressure had no significant difference compared to the flat-bottomed shoes. As walking with rocker sole shoes resulted in decreased forces and pressures under the forefoot but increased overload at heel and midfoot regions, obese individuals may not benefit from wearing rocker sole shoes during walking, at least from a plantar pressure distribution perspective.Implications for rehabilitationThe use of ergonomic rocker sole shoes causes a redistribution of in-shoe plantar pressures leading to potentially detrimental adjustments that fail to attenuate the obesity-related increase in midfoot pressure during standing, while accentuating this region-specific impairment in dynamic conditions.Rocker sole shoes may best be avoided for walking in obese patients with heel pain or with any midfoot/rearfoot alteration such as medial arch flattening.

The foot is a complex system with multiple degrees of freedom that play an essential role in running or sprinting. The intrinsic foot muscles (IFM) are the main local stabilizers of the foot and are part of the active and neural subsystems that constitute the foot core. These muscles lengthen eccentrically during the stance phase of running before shortening at the propulsion phase, as the arch recoils in parallel to the plantar fascia. They play a key role in supporting the medial longitudinal arch, providing flexibility, stability and shock absorption to the foot, whilst partially controlling pronation. Much of the foot rigidity in late stance has been attributed to the windlass mechanism - the dorsiflexion of the toes building tension up in the plantar aponeurosis and stiffening the foot. In addition, recent studies have shown that the IFM provide a necessary active contribution in late stance, in order to develop sufficient impedance in the metatarsal-phalangeal joints. This in turn facilitates the propulsive forces at push-off. These factors support the critical role of the foot in providing rigidity and an efficient lever at push-off. During running or sprinting, athletes need to generate and maintain the highest (linear) running velocity during a single effort in a sprinting lane. Acceleration and sprinting performance requires forces to be transmitted efficiently to the ground. It may be of particular interest to strengthen foot muscles to maintain and improve an optimal capacity to generate and absorb these forces. The current evidence supports multiple exercises to achieve higher strength in the foot, such as the "short foot exercise," doming, toes curl, towing exercises or the more dynamic hopping exercises, or even barefoot running. Their real impact on foot muscle strength remains unclear and data related to its assessment remains scarce, despite a recognized need for this, especially before and after a strengthening intervention. It would be optimal to be able to assess it. In this article, we aim to provide the track and field community with an updated review on the current modalities available for foot strength assessment and training. We present recommendations for the incorporation of foot muscles training for performance and injury prevention in track and field., (Copyright © 2019 Tourillon, Gojanovic and Fourchet.)

Competing Interests: Competing interests: None declared.

Objectives: To examine the association between generalised joint laxity (GJL) and injury rates in Middle Eastern male youth athletes., Design: Prospective observational study consisting of GJL screen and injury audit (season 2009/2010)., Setting: Aspire Sports Academy Doha, Qatar., Participants: A total of 226 adolescent male athletes (mean age: 14.2 years; SD: 1.7; range: 10-18) involved in 15 sporting activities were grouped into contact and non-contact sports. All available athletes were included in this study., Outcome Measures: A seasonal injury audit, athletes' anthropometric characteristics, for example, weight, height and body mass index and screen for GJL to determine Beighton Score (BS)., Results: The 226 athletes sustained 596 injuries and 75% reported at least one injury over a seasonal injury audit. Players in contact sports were injured more often than players in non-contact sports (more frequent injuries than injury-free time in contact sports; 127 days (95% CI 93 to 160) vs 176 days in non-contact sports (95% CI 118 to 234) (p<0.001). Survival analysis showed that gradient BS was not associated with injury HR=1.004 (95% CI 0.95 to 1.06) in the overall cohort. However, BS was associated with a greater injury risk in contact sports (HR: 1.29; 95% CI 1.05 to 1.59; p=0.015)., Conclusion: Greater GJL, defined by gradient BS, plus involvement in contact sports together influence injury risk in youth athletes. Preseason documentation of GJL scoring should be considered specifically for contact sports as injury pre-emptive measure., Competing Interests: Competing interests: None declared.

Lateral ankle sprain injury is the most common musculoskeletal injury incurred by individuals who participate in sports and recreational physical activities. Following initial injury, a high proportion of individuals develop long-term injury-associated symptoms and chronic ankle instability. The development of chronic ankle instability is consequent on the interaction of mechanical and sensorimotor insufficiencies/impairments that manifest following acute lateral ankle sprain injury. To reduce the propensity for developing chronic ankle instability, clinical assessments should evaluate whether patients in the acute phase following lateral ankle sprain injury exhibit any mechanical and/or sensorimotor impairments. This modified Delphi study was undertaken under the auspices of the executive committee of the International Ankle Consortium. The primary aim was to develop recommendations, based on expert (n=14) consensus, for structured clinical assessment of acute lateral ankle sprain injuries. After two modified Delphi rounds, consensus was achieved on the clinical assessment of acute lateral ankle sprain injuries. Consensus was reached on a minimum standard clinical diagnostic assessment. Key components of this clinical diagnostic assessment include: establishing the mechanism of injury, as well as the assessment of ankle joint bones and ligaments. Through consensus, the expert panel also developed the International Ankle Consortium Rehabilitation-Oriented ASsessmenT (ROAST). The International Ankle Consortium ROAST will help clinicians identify mechanical and/or sensorimotor impairments that are associated with chronic ankle instability. This consensus statement from the International Ankle Consortium aims to be a key resource for clinicians who regularly assess individuals with acute lateral ankle sprain injuries., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: Ankle sprain is the most common sport-related injury and eccentric weakness of ankle evertors is regarded as a significant muscular deficit related to chronic ankle instability. However, the eccentric performance of the evertors is rarely assessed by clinicians because procedures used for research purposes (i.e. isokinetic tests) are not easily applicable in daily practice., Methods: The present study assessed the ability of two different testing procedures to distinguish between groups of 12 healthy subjects or 12 patients suffering from chronic ankle instability. On the one hand, the strength of evertors was assessed with a goldstandard isokinetic procedure. On the other hand, we assessed the ability of the subjects to control ankle inversion during weight bearing (functional standing test)., Findings: Data showed no significant difference between groups for isokinetic peak torque values normalized to body weight. Conversely, the functional test revealed a significantly impaired ability to control ankle inversion during weight bearing in subjects with chronic ankle instability., Interpretation: This suggests that this easy-to-apply functional test is better suited compared to isokinetic testing procedures to assess weakness of evertors in patients suffering from chronic ankle instability. Moreover, this test may also be used to objectively monitor improvements during rehabilitation or progression in prevention protocols., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Lateral ankle sprains (LASs) are the most prevalent musculoskeletal injury in physically active populations. They also have a high prevalence in the general population and pose a substantial healthcare burden. The recurrence rates of LASs are high, leading to a large percentage of patients with LAS developing chronic ankle instability. This chronicity is associated with decreased physical activity levels and quality of life and associates with increasing rates of post-traumatic ankle osteoarthritis, all of which generate financial costs that are larger than many have realised. The literature review that follows expands this paradigm and introduces emerging areas that should be prioritised for continued research, supporting a companion position statement paper that proposes recommendations for using this summary of information, and needs for specific future research., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

The Executive Committee of the International Ankle Consortium presents this 2016 position paper with recommendations for information implementation and continued research based on the paradigm that lateral ankle sprain (LAS), and the development of chronic ankle instability (CAI), serve as a conduit to a significant global healthcare burden. We intend our recommendations to serve as a mechanism to promote efforts to improve prevention and early management of LAS. We believe this will reduce the prevalence of CAI and associated sequelae that have led to the broader public health burdens of decreased physical activity and early onset ankle joint post-traumatic osteoarthritis. Ultimately, this can contribute to healthier lifestyles and promotion of physical activity., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

The intrinsic muscles of the foot play a critical role in the regulation of absorption and propulsion during dynamic activities. Dysfunction of these may lead to an increased demand on the remaining components within the foot core system to maintain dynamic foot control, leading to a more rapid breakdown of these contributors and those proximal to the foot. Training the intrinsic foot muscles through a systematic progression of isolation via the short foot exercise offers the opportunity to reincorporate their contribution into the foot core system. This article discusses the function of the intrinsic foot muscles, their contributions to dynamic foot control, and a progressive training paradigm., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objectives: This study aimed to determine adjustments in spring-mass model characteristics, plantar loading and foot mobility induced by an exhaustive run., Design: Within-participants repeated measures., Methods: Eleven highly-trained adolescent middle-distance runners ran to exhaustion on a treadmill at a constant velocity corresponding to 95% of velocity associated with VO₂max (17.8 ± 1.4 kmh(-1), time to exhaustion=8.8 ± 3.4 min). Contact time obtained from plantar pressure sensors was used to estimate spring-mass model characteristics, which were recorded (during 30 s) 1 min after the start and prior to exhaustion using pressure insoles. Foot mobility magnitude (a composite measure of vertical and medial-lateral mobility of the midfoot) was measured before and after the run., Results: Mean contact area (foot to ground), contact time, peak vertical ground reaction force, centre of mass vertical displacement and leg compression increased significantly with fatigue, while flight time, leg stiffness and mean pressure decreased. Leg stiffness decreased because leg compression increased to a larger extent than peak vertical ground reaction forces. Step length, step frequency and foot mobility magnitude did not change at exhaustion., Conclusions: The stride pattern of adolescents when running on a treadmill at high constant velocity deteriorates near exhaustion, as evidenced by impaired leg-spring behaviour (leg stiffness) and altered plantar loading., (Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Context: Fatigue-induced alterations in foot mechanics may lead to structural overload and injury., Objectives: To investigate how a high-intensity running exercise to exhaustion modifies ankle plantar-flexor and dorsiflexor strength and fatigability, as well as plantar-pressure distribution in adolescent runners., Design: Controlled laboratory study., Setting: Academy research laboratory., Patients or Other Participants: Eleven male adolescent distance runners (age = 16.9 ± 2.0 years, height = 170.6 ± 10.9 cm, mass = 54.6 ± 8.6 kg) were tested., Intervention(s): All participants performed an exhausting run on a treadmill. An isokinetic plantar-flexor and dorsiflexor maximal-strength test and a fatigue test were performed before and after the exhausting run. Plantar-pressure distribution was assessed at the beginning and end of the exhausting run., Main Outcome Measure(s): We recorded plantar-flexor and dorsiflexor peak torques and calculated the fatigue index. Plantar-pressure measurements were recorded 1 minute after the start of the run and before exhaustion. Plantar variables (ie, mean area, contact time, mean pressure, relative load) were determined for 9 selected regions., Results: Isokinetic peak torques were similar before and after the run in both muscle groups, whereas the fatigue index increased in plantar flexion (28.1%; P = .01) but not in dorsiflexion. For the whole foot, mean pressure decreased from 1 minute to the end (-3.4%; P = .003); however, mean area (9.5%; P = .005) and relative load (7.2%; P = .009) increased under the medial midfoot, and contact time increased under the central forefoot (8.3%; P = .01) and the lesser toes (8.9%; P = .008)., Conclusions: Fatigue resistance in the plantar flexors declined after a high-intensity running bout performed by adolescent male distance runners. This phenomenon was associated with increased loading under the medial arch in the fatigued state but without any excessive pronation.

While research on chronic ankle instability (CAI) and awareness of its impact on society and health care systems has grown substantially in the last 2 decades, the inconsistency in participant/patient selection criteria across studies presents a potential obstacle to addressing the problem properly. This major gap within the literature limits the ability to generalise this evidence to the target patient population. Therefore, there is a need to provide standards for patient/participant selection criteria in research focused on CAI with justifications using the best available evidence. The International Ankle Consortium provides this position paper to present and discuss an endorsed set of selection criteria for patients with CAI based on the best available evidence to be used in future research and study designs. These recommendations will enhance the validity of research conducted in this clinical population with the end goal of bringing the research evidence to the clinician and patient., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

The International Ankle Consortium is an international community of researchers and clinicians whose primary scholastic purpose is to promote scholarship and dissemination of research-informed knowledge related to pathologies of the ankle complex. The constituents of the International Ankle Consortium and other similar organizations have yet to properly define the clinical phenomenon known as chronic ankle instability (CAI) and its related characteristics for consistent patient recruitment and advancement of research in this area. Although research on CAI and awareness of its impact on society and healthcare systems have grown substantially in the last 2 decades, the inconsistency in participant/patient selection criteria across studies presents a potential obstacle to addressing the problem properly. This major gap within the literature limits the ability to generalize this evidence to the target patient population. Therefore, there is a need to provide standards for patient/participant selection criteria in research focused on CAI, with justifications using the best available evidence.

Objectives: To evaluate the reliability level of an innovative method using a standardized stretch force to assess the flexibility of lower limb muscle groups in highly-trained adolescent athletes and to examine whether interchanging the examiners affects the reliability of the measures., Design: Randomized test-retest study., Setting and Participants: In ten athletes, the flexibility of eight lower limb muscle groups was examined on two occasions on both sides and in two phases: a video capture by three distinct operators and an analysis by three distinct analysers. The reliability of the measures was assessed by the coefficient of variation (CV, 90% CI). Between-analysers and between-operators standardized differences (i.e., Cohen's d) were calculated., Results: CV (%, 90% CI) were 8.3% (7.5; 9.3) for quadriceps, 3.3% (3.0; 3.7) for hamstrings, 7.2% (6.5-8.0) for adductors, 5.7% (5.1; 6.3) for gastrocnemius, 4.5% (4.0; 5.0) for soleus, 2.6% (2.3; 2.9) for hip flexors, 9.6% (8.6; 10.8) for hip medial rotators and 12.4% (12.2; 14.0) for hip lateral rotators. There was no substantial (i.e., Cohen's d < 0.2) difference in CV between all the possible operators/analysers combinations., Conclusion: This method has a moderate-to-good reliability level and is examiner-independent. It may be implemented in future injury prevention programs, in order to monitor the flexibility of highly-trained adolescent athletes., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The aim of this study was to investigate changes in running mechanics and spring-mass behaviour with fatigue induced by 5-hour hilly running (5HHR). Running mechanics were measured pre- and post-5HHR at 10, 12 and 14 km · h(-1) on an instrumented treadmill in eight ultramarathon runners, and sampled at 1000 Hz for 10 consecutive steps. Contact (t(c) ) and aerial (t(a) ) times were determined from ground reaction force (GRF) signals and used to compute step frequency (f). Maximal GRF, loading rate, downward displacement of the centre of mass (Δz), and leg length change (ΔL) during the support phase were determined and used to compute both vertical (K(vert) ) and leg (K(leg) ) stiffness. A significant decrease in t(c) was observed at 12 and 14 km · h(-1) resulting in an increase of f at all speeds. Duty factor and F(max) significantly decreased at 10 km · h(-1). A significant increase in K(vert) and K(leg) was observed at all running speeds with significant decreases in Δz and ΔL. Despite the shorter duration, the changes in running mechanics appeared to be in the same direction (increased f and K(vert) , decrease in Δz and F(max) ) but of lower amplitude compared with those obtained after an ultra-trail or an ultramarathon.

Context: A passive knee-extension test has been shown to be a reliable method of assessing hamstring tightness, but this method does not take into account the potential effect of gravity on the tested leg., Objective: To compare an original passive knee-extension test with 2 adapted methods including gravity's effect on the lower leg., Design: Repeated measures., Setting: Laboratory., Participants: 20 young track and field athletes (16.6 ± 1.6 y, 177.6 ± 9.2 cm, 75.9 ± 24.8 kg)., Intervention: Each subject was tested in a randomized order with 3 different methods: In the original one (M1), passive knee angle was measured with a standard force of 68.7 N (7 kg) applied proximal to the lateral malleolus. The second (M2) and third (M3) methods took into account the relative lower-leg weight (measured respectively by handheld dynamometer and anthropometrical table) to individualize the force applied to assess passive knee angle., Main Outcome Measures: Passive knee angles measured with video-analysis software., Results: No difference in mean individualized applied force was found between M2 and M3, so the authors assessed passive knee angle only with M2. The mean knee angle was different between M1 and M2 (68.8 ± 12.4 vs 73.1 ± 10.6, P < .001). Knee angles in M1 and M2 were correlated (r = .93, P < .001)., Conclusions: Differences in knee angle were found between the original passive knee-extension test and a method with gravity correction. M2 is an improved version of the original method (M1) since it minimizes the effect of gravity. Therefore, we recommend using it rather than M1.