Field Hip Stability Isometric Test (F-HipSIT): Reliability of Assessing the Hip Posterolateral Muscle Strength in Sports Settings.

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.

Post-match recovery of eccentric knee flexor strength in male professional football players.

OBJECTIVES: This study aimed at verifying the effect of a football match on the eccentric knee flexor strength of male professional players along a 72-h period. STUDY DESIGN: Quasi-experimental study. SETTING: Football club facilities. PARTICIPANTS: Fifteen players were assessed in four timepoints: 24 h before, immediately after, 48 h and 72 h after the match. MAIN OUTCOME MEASURES: The eccentric knee flexor strength was assessed during the Nordic hamstring exercise execution. RESULTS: Players presented a significant strength reduction immediately after match (Δ = 12%; p = 0.001; large effect size, d = 1.10), and did not recover their strength capacity within a 48 h-period (Δ = 6%; p = 0.011; moderate effect size, d = 0.57). At 72 h after the match, strength was similar to baseline levels (Δ = 3.5%; p = 0.122; small effect size, d = 0.34). Secondarily, individual response analysis considered a player 'fully recovered' when his strength deficit compared to the baseline measure was lower than the measurement coefficient of variation (i.e., <5%). Only 6 (40%) and 9 (60%) players were 'fully recovered' at 48 h and 72 h after the match, respectively. CONCLUSION: Professional football players experienced an immediately post-match drop on the eccentric knee flexor strength, and significant strength deficits persisted for a 48-h period. Some players were not recovered at 72 h after the match.

A FOUR-WEEK TRAINING PROGRAM WITH THE NORDIC HAMSTRING EXERCISE DURING PRESEASON INCREASES ECCENTRIC STRENGTH OF MALE SOCCER PLAYERS.

BACKGROUND: The Nordic hamstring exercise (NHE) is an effective strategy to prevent hamstring strain injuries in soccer players. The current literature recommends a 10-week training program with three sessions per week, but the short preseason period and the congested schedule make difficult for high-performance soccer teams to apply the NHE as recommended. PURPOSE: The purpose of this study was to examine the effect of a pragmatic NHE training program during a four-week preseason period on eccentric knee flexor strength of high-performance soccer players. STUDY DESIGN: Quasi-experimental clinical trial. METHODS: This study included 25 under-20 male soccer players from a premier league club. They performed eight sessions of NHE (3 sets of 6-10 repetitions, twice a week) during the four-week preseason period. The eccentric knee flexor strength was evaluated during the NHE execution on a custom-made device, before and after the training program. RESULTS: The NHE training program significantly increased the players' eccentric knee flexor strength in both right (Δ = 13%; p<0.001; effect size = 0.97) and left limbs (Δ = 13%; p<0.001; effect size = 0.92). Individual analysis identified 76% of the players as responders to the NHE training program (Δ = 16%; effect size = 1.60), and 24% as non-responders (Δ = 3%; effect size = 0.24). CONCLUSION: A four-week training program with NHE performed twice a week is feasible in the real-world of high-performance soccer clubs and increases the eccentric knee flexor strength of male soccer players.

ACCURACY OF THE FUNCTIONAL MOVEMENT SCREEN (FMSTM) ACTIVE STRAIGHT LEG RAISE TEST TO EVALUATE HAMSTRING FLEXIBILITY IN SOCCER PLAYERS.

BACKGROUND: Poor flexibility is considered a risk factor for the hamstring strain injury, and the active straight leg raise (ASLR) test proposed as a part of the Functional Movement Screen™ (FMS™) has been used to assess athletes hamstring flexibility. However, the accuracy of this screening test remains undescribed. PURPOSE: To examine the accuracy of the FMS™ ASLR test for assessment of hamstring flexibility in soccer players. STUDY DESIGN: Cross-sectional study. METHODS: One-hundred and one male soccer players (age, 21 ± 3 years; height, 179 ± 7 cm; weight, 75 ± 9 kg) were bilaterally evaluated. All players performed a gold standard test for hamstring flexibility evaluation: the passive straight leg raise (PSLR) test measured using a gravitational inclinometer. All players also performed the ASLR test and were scored using the criteria proposed by the FMS™. RESULTS: Of the 202 lower limbs evaluated, 17.82% scored a 1 on the ASLR [mean passive flexibility: 80.44 ± 14.69 ° (55 °-110 °)], 50.99% scored a 2 on the ASLR [mean passive flexibility = 84.60 ± 10.59 ° (56 °-115 °)], and 31.18% scored a 3 on the ASLR [mean passive flexibility = 92.32 ± 11.53 ° (70 °-120 °)]. Limbs with FMS™ score of 3 presented significantly higher values for passive flexibility than limbs with scores of 1 and 2 (p < 0.05), but there was no significant difference between limbs with scores of 1 and 2 (p > 0.05). CONCLUSION: The score obtained in the FMS™ ASLR test does not satisfactorily stratify the level of hamstring flexibility in soccer players. LEVEL OF EVIDENCE: 3a.

Inter-machine reliability of the Biodex and Cybex isokinetic dynamometers for knee flexor/extensor isometric, concentric and eccentric tests.

OBJECTIVES: To assess the inter-machine reliability of the Biodex System 3 Pro and Cybex Humac Norm Model 770 dynamometers for knee extensor and knee flexor peak torque measurements in isometric, concentric and eccentric tests. DESIGN: Randomized/crossover. SETTING: Exercise Research Laboratory, Federal University of Rio Grande do Sul (Brazil). PARTICIPANTS: 25 healthy male subjects. MAIN OUTCOME MEASURES: Isometric, concentric and eccentric knee extensor and knee flexor peak torques recorded in the same test procedure performed on both isokinetic dynamometers. One-way ANOVA, intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of variation (CV) were used to verify significant differences, relative and absolute reliability between devices. RESULTS: No significant differences were found between tests performed on Biodex and Cybex (p > 0.05). ICC values indicated a high to very high reproducibility for isometric, concentric and eccentric peak torques (0.88-0.92), and moderate to high reliability for agonist-antagonist strength ratios (0.62-0.73). Peak torque did not show great difference between dynamometers for SEM (3.72-11.27 Nm) and CV (5.27-7.77%). Strength ratios presented CV values of 8.57-10.72%. CONCLUSION: Maximal knee extensor and knee flexor tests performed in isometric (60° of knee flexion), concentric and eccentric modes at 60°/s in Biodex and Cybex dynamometers present similar values.