Context: Hip muscle strength has previously been evaluated in various sagittal plane testing positions. Altering the testing position appears to have an influence on hip muscle torque during hip extension, abduction, and external rotation. However, it is unknown how altering the testing position influences hip muscle activity during these commonly performed assessments. Objectives: To evaluate how hip sagittal plane position influences hip muscle activation and torque output. Study Design: Cross-sectional. Setting: Laboratory. Patients or Other Participants: A total of 22 healthy females (age = 22.1 [1.4] y; mass = 63.4 [11.3] kg; height = 168.4 [6.2] cm) were recruited. Intervention: None. Main Outcome Measures: Participants completed isometric contractions with surface electromyography on the superior and inferior gluteus maximus; anterior, middle, and posterior gluteus medius; biceps femoris, semitendinosus, adductor longus, and tensor fascia latae. Extension and external rotation were tested in 0°, 45°, and 90° of hip flexion and abduction was tested in −5°, 0°, and 45° of hip flexion. Repeated-measures analysis of variances were used for statistical analysis (P ≤ .01). Results: Activation of gluteal (P < .007), semitendinosus (P = .002), and adductor longus (P = .001) muscles were lesser for extension at 90° versus less flexed positions. Adductor longus activity was greatest during 90° of hip flexion for external rotation torque testing (P < .001). Tensor fascia latae (P < .001) and gluteus maximus (P < .001) activities were greater in 45° of hip flexion. Significant differences in extension (P < .001) and abduction (P < .001) torque were found among positions. Conclusions: Position when assessing hip extension and abduction torque has an influence on both muscle activity and torque output but only muscle activity for hip external rotation torque. Clinicians should be aware of the influence of position on hip extension, abduction, and external rotation muscle testing and select a position most in line with their clinical goals.
Neal R. Glaviano and David M. Bazett-Jones
Damien Clement and Monna Arvinen-Barrow
Context: A multidisciplinary approach is one of the many forms of professional practice that can be utilized by sports medicine professionals to provide care to injured athletes. While this approach has been empirically supported in the health care domain, studies supporting its utilization in the sport injury rehabilitation context—particularly at the high school level—are limited. Objective: To investigate former high school athletes’ experiences of a multidisciplinary model of care for sport injury rehabilitation. Design: Cross-sectional survey design. Setting: In-person, in a classroom setting at 2 Division I universities. Patients: A total of 186 former high school athletes. Main Outcome Measure: An author-constructed instrument developed using the multidisciplinary model of care for sport injury rehabilitation as a guide. Results: Family, athletic coaches, and athletic trainers were the closest professionals/individuals that injured athletes reported interacting with during sport injury rehabilitation. The data also revealed that these professionals/individuals had the closest and most direct relationships with the injured athletes. Conclusions: The findings from the present study provided support for the utilization of the multidisciplinary model of care for sport injury rehabilitation with high school athletes.
Alexandre H. Nowotny, Mariane Guizeline Calderon, Bruno Mazziotti O. Alves, Marcio R. de Oliveira, Rodrigo A. de Carvalho Andraus, Andreo F. Aguiar, Cesar F. Amorim, Guillaume Leonard, and Rubens A. da Silva
Context: Chronic low-back pain (CLBP) may be associated with changes in postural balance in athletes as poor postural control during sports practice. Objective: To compare the postural control of athletes with and without CLBP during 2 one-legged stance tasks and identify the center of pressure (COP) cutoff values to determine the main differences. Designed: A cross-sectional study. Setting: Laboratory of functional evaluation and human motor performance. Participants: A total of 56 male athletes, 28 with and 28 without CLBP (mean age = 26 y). Intervention: The one-legged stance with knee extension and with the knee at 30° flexion tasks were measured and analyzed on a force platform. The participants completed three 30-second trials (30 s of rest between each trial). Main Outcome Measures: The COP parameters: the area of COP, mean COP sway velocity in both the anteroposterior and mediolateral directions, and total COP displacement were computed, and a receiver operating characteristics curve analysis was applied to determine the group differences. Results: Athletes with CLBP had poorer postural control (P < .01) in both tasks. The 30° knee flexion reported more postural instability than the knee extension for all COP parameters (a large effect size d = 0.80).The knee extension cutoffs identified were >7.1 cm2 for the COP area, >2.6 cm/s for the COP sway velocity in the anterior-posterior direction, and >3.2 cm/s for the mediolateral direction. Whereas, the 30° knee flexion cutoffs were >10.9 cm2 for the COP area, >2.9 cm/s for the COP sway velocity in the anterior-posterior direction, and >4.1 cm/s for the mediolateral direction. Both measures showed enough sensitivity and specificity (ie, area under the curve = 0.88 in and 0.80, respectively) to discriminate both groups. Conclusions: The athletes with CLBP had poorer postural control than the healthy athletes and obtained specific cutoff scores from the COP values.
Yi Wang, Wing K. Lam, Charis K. Wong, Lok Y. Park, Mohammad F. Tan, and Aaron K.L. Leung
This study examined the effect of foot orthoses used on ground reaction forces, ankle, and knee kinematics when running at preferred and nonpreferred speeds. Sixteen runners ran on instrumented treadmills at various speeds (90%, 100%, and 110% of preferred speed) when wearing arch-support and flat-control orthoses. Two-way repeated analysis of variance (ANOVA) was performed on the mean and coefficient of variation of all variables. Results indicated that arch-support orthoses experienced larger maximum loading rates than flat-control orthoses (P = .017, 95% CI, 2.22 to 19.53). Slower speed was related to smaller loading rates (preferred: P = .002, 95% CI, −17.02 to −4.20; faster: P = .003, 95% CI, −29.78 to −6.17), shorter stride length (preferred: P < .001, 95% CI, −0.204 to −0.090; faster: P < .001, 95% CI, −0.382 to −0.237), and longer contact time (preferred: P < .001, 95% CI, 0.006–0.021; faster: 95% CI, 0.012–0.042). In arch-support condition, preferred speed induced higher stride length coefficient of variation (P = .046, 95% CI, 0.035–1.117) than faster speed, while displaying no differences in flat-control condition. These findings suggest that the use of arch-support orthoses would influence impact loading, but not spatial-temporal and joint kinematics in recreational runners.
Itsuroh Shimizu, Hiroichi Miaki, Katsunori Mizuno, Nobuhide Azuma, Takao Nakagawa, and Toshiaki Yamazaki
Context: Lumbar instability can cause lumbar spondylolisthesis and chronic low-back pain in sports situation. Abdominal hollowing is commonly used in clinical practice to preferentially target the transversus abdominis (TrA) to stabilize the lumbar vertebrae; however, the contribution of muscle elasticity and lateral slide of the TrA to lumbar stability has not yet been clarified. Objective: To clarify the contribution of elasticity and lateral slide of the TrA to lumbar stability and to identify an effective exercise to stabilize the lumbar vertebrae. Design: Experimental study. Setting: Laboratory. Patients: A total of 29 healthy males participated in this study. Interventions: The participants performed hollowing during measurement of muscle elasticity of TrA and both knees extension from crook lying position for pelvic stability measurement. Main Outcome Measures: Lumbar stability, muscle elasticity change ratio, and lateral slide amount of TrA. Results: There was a significant correlation between elasticity of the TrA and lumbar stability; however, no relationship was observed between lateral slide and lumbar stability or elasticity of the TrA. Conclusion: Elasticity of the TrA and lumbar stability was significantly correlated; therefore, improving the tonicity of the TrA may stabilize the lumbar vertebrae in healthy individuals. Moreover, hollowing with maximum effort may be effective as training aimed to stabilize the lumbar vertebrae for physical dysfunction due to lumbar instability.
John H. Hollman, Nicholas J. Beise, Michelle L. Fischer, and Taylor L. Stecklein
Context: Examining the coordinated coupling of muscle recruitment patterns may provide insight into movement variability in sport-related tasks. Objective: The purpose of this study was to examine the relationship between coupled gluteus maximus and medius recruitment patterns and hip-adduction variability during single-limb step-downs. Design: Cross-sectional. Setting: Biomechanics laboratory. Participants: Forty healthy adults, including 26 women and 14 men, mean age 23.8 (1.6) years, mean body mass index 24.2 (3.1) kg/m2, participated. Interventions: Lower-extremity kinematics were acquired during 20 single-limb step-downs from a 19-cm step height. Electromyography (EMG) signals were captured with surface electrodes. Isometric hip-extension strength was obtained. Main Outcome Measures: Hip-adduction variability, measured as the SD of peak hip adduction across 20 repetitions of the step-down task, was measured. The mean amplitudes of gluteus maximus and gluteus medius EMG recruitment were examined. Determinism and entropy of the coupled EMG signals were computed with cross-recurrence quantification analyses. Results: Hip-adduction variability correlated inversely with determinism (r = −.453, P = .018) and positively with entropy (r = .409, P = .034) in coupled gluteus maximus/medius recruitment patterns but not with hip-extensor strength nor with magnitudes of mean gluteus maximus or medius recruitment (r = −.003, .081, and .035; P = .990, .688, and .864, respectively). Conclusion: Hip-adduction variability during single-limb step-downs correlated more strongly with measures of coupled gluteus maximus and medius recruitment patterns than with hip-extensor strength or magnitudes of muscle recruitment. Examining coupled recruitment patterns may provide an alternative understanding of the extent to which hip neuromuscular control modulates lower-extremity kinematics beyond examining muscle strength or EMG recruitment magnitudes.
Christopher Michael Brogden, Lewis Gough, and Adam Kelly
Context: Physiological fitness testing, such as the Yo-Yo Intermittent Recovery Test (YYIR) is a key requirement of the Elite Player Performance Plan, introduced by the English Premier League. Eccentric hamstring strength has been identified as a risk factor for hamstring injuries in soccer players, with fatigue highlighted to further exasperate this issue. Objective: The aim of the current study was to examine the effect of the YYIR level 1 (YYIR1) on eccentric knee flexor strength assessed using the NordBord in youth soccer players. Design: Experimental design. Setting: Soccer club academy. Participants: A total of 67 male academy soccer players (age = 16.58 [0.57] y; height = 175.45 [5.85] cm; mass = 66.30 [8.21] kg) volunteered to participate in the current study during the English competitive soccer season. Main Outcome Measures: Participants conducted eccentric hamstring strength assessments using the NordBord prior to and immediately postcompletion of the YYIR1, with outcome measures of peak force and peak force relative to body mass recorded. Results: Paired t tests highlighted increased absolute eccentric knee flexor strength values (P < .001) immediately post-YYIR1 for both the dominant and nondominant limbs, with the same trend (P < .001) observed for eccentric strength relative to body mass. Conclusions: The results of this study indicate that the YYIR1 does not induce eccentric knee flexor fatigue and as such is not a valid assessment method to assess the effects of fatigue on hamstring function. However, results do suggest that the NordBord may be considered a viable and more accessible alternative to detect pre–post fitness test/fatigue protocol differences in eccentric knee flexor peak strength while working in the field.
Audrey G. Evers, Jessica A Somogie, Ian L. Wong, Jennifer D. Allen, and Adolfo G. Cuevas
The objective of this study was to examine the effectiveness of a pilot mindfulness program for student athletes by assessing mental health, mindfulness ability, and perceived stress before and after the intervention. The mindfulness program was adapted from a program developed at the University of Southern California. The four-session intervention taught the basics of mindfulness, self-care skills, and guided meditations. Participants completed surveys before and after the intervention. Mindfulness ability was assessed with the Cognitive and Affective Mindfulness Scale, mental health was assessed with a modified Short Form Health Survey, and stress was assessed with the Perceived Stress Scale. After the intervention, participants reported improvement in mindfulness ability, t(28) = −2.61, p = .014, mental health, t(28) = −2.87, p = .008, and a trending improvement in perceived stress, t(28) = 1.86, p = .073. A short mindfulness program may be effective for improving mental health and mindfulness ability in collegiate student athletes.
Luca Correale, Vittoria Carnevale Pellino, Luca Marin, Massimiliano Febbi, and Matteo Vandoni
Spatiotemporal parameters of walking are used to identify gait impairments and provide a tailored therapy program. Baropodometric platforms are not often used for measuring spatiotemporal parameters and walking speed and it is required to determine accuracy. The aim of this study was to compare FreeMed® Platform gait outcomes with a validated inertial measurement unit. There were 40 healthy adults without walking impairments enrolled. Each subject walked along a 15-m walkway at self and slow self-selected speed wearing an inertial measurement unit on the FreeMed® Platform. Stride length and time, right and left stance, swing time, and walking speed were recorded. Walking speed, stride length, and step time showed a very high level of agreement at slow walking speed and a high and moderate level of agreement at normal walking speed. FreeMed® Platform is useful to assess gait outcomes and could improve the exercise prescription.