Context: The squat is a fundamental movement for weightlifting and sports performance. Both unilateral and bilateral squats are also used to assess transitional and dynamic lower-extremity control. Common lower-extremity conditions can have an influence on squat performance. Of interest are the effects of hip musculoskeletal conditions and associated factors, such as hip muscle pain, fatigue, and tightness, on squat performance. Currently, there has been no appraisal of the evidence regarding the association of these conditions and associated factors on squat performance. Objective: This study evaluated the current evidence regarding common hip musculoskeletal conditions and associated factors, such as hip muscle pain, fatigue, and tightness, on squat performance. Evidence Acquisition: A systematic review was conducted according to preferred reporting items for systematic reviews and meta-analyses guidelines. A search of PubMed, CINAHL, SPORTDiscus, ProQuest, and Google Scholar® was conducted in October, 2016 using the following keywords alone and in combination: hip, joint, arthritis, pain, range of motion (ROM), fatigue, tightness, pathology, condition, muscle, intraarticular, extraarticular, femoroacetabular impingement, single leg, bilateral, squat, performance, and technique. The grading of studies was conducted using the Physiotherapy Evidence Database scale. Evidence Synthesis: The authors identified 35 citations, 15 of which met the inclusion criteria. The qualifying studies yielded a total of 542 subjects (160 men and 382 women; mean age = 29.3 (5.9) y) and measured performance with either the barbell squat, step down, bilateral, or single-leg squat. Femoroacetabular impingement and hip arthroscopy were the only hip conditions found that affected the squat. Associated factors, such as muscle pain, fatigue, and tightness, also influenced squat performance. Conclusion: This review found that common hip conditions and associated factors and their effects on squat performance to be underinvestigated. Future research should focus on the association between common hip conditions and squat performance.
Scott W. Cheatham, Kyle R. Stull, Mike Fantigrassi and Ian Montel
Richard A. Brindle, David Ebaugh and Clare E. Milner
Context: Side-lying hip abductor strength tests are commonly used to evaluate muscle strength. In a “break” test, the tester applies sufficient force to lower the limb to the table while the patient resists. The peak force is postulated to occur while the leg is lowering, thus representing the participant’s eccentric muscle strength. However, it is unclear whether peak force occurs before or after the leg begins to lower. Objectives: To determine intrarater reliability and construct validity of a hip abductor eccentric strength test. Design: Intrarater reliability and construct validity study. Participants: Twenty healthy adults (26  y; 1.66 [0.06] m; 62.2 [8.0] kg) made 2 visits to the laboratory at least 1 week apart. Main Outcome Measures : During the hip abductor eccentric strength test, a handheld dynamometer recorded peak force and time to peak force, and limb position was recorded via a motion capture system. Intrarater reliability was determined using intraclass correlation, SEM, and minimal detectable difference. Construct validity was assessed by determining if peak force occurred after the start of the lowering phase using a 1-sample t test. Results: The hip abductor eccentric strength test had substantial intrarater reliability (intraclass correlation(3,3) = .88; 95% confidence interval, .65–.95), SEM of 0.9 %BWh, and a minimal detectable difference of 2.5 %BWh. Construct validity was established as peak force occurred 2.1 (0.6) seconds (range: 0.7–3.7 s) after the start of the lowering phase of the test (P ≤ .001). Conclusion: The hip abductor eccentric strength test is a valid and reliable measure of eccentric muscle strength. This test may be used clinically to assess changes in eccentric muscle strength over time.
Robert W. Cox, Rodrigo E. Martinez, Russell T. Baker and Lindsay Warren
Context: Range of motion is a component of a physical examination used in the diagnostic and rehabilitative processes. Following ankle injury and/or during research, it is common to measure plantar flexion with a universal goniometer. The ease and availability of digital inclinometers created as applications for smartphones have led to an increase in using this method of range of motion assessment. Smartphone applications have been validated as alternatives to inclinometer measurements in the knee; however, this application has not been validated for plantar flexion in the ankle. Objectives: The purpose of this study was (1) to assess the validity of the Clinometer Smartphone Application™ produced by Plaincode App Development for use in the ankle (ie, plantar flexion) and (2) to assess the validity of the inclinometer procedures used to measure ankle dorsiflexion for measuring ankle plantar flexion. Design: Blinded repeated measures correlational design. Setting: University-based outpatient rehabilitative clinic. Participants: A convenience sample (N = 50) of participants (27 females and 23 males) who reported to the clinic (mean age = 30.48 y). Intervention: Patients were long seated on a plinth, with the knee in terminal extension. Three plantar flexion measurements were taken with a goniometer on each foot by the primary researcher. The primary researcher then conducted 3 blinded measurements with The Clinometer Smartphone Application™ following the same procedure. A second researcher, who was blinded to the goniometer measurements, recorded the inclinometer measurements. After data were collected, a Pearson’s correlation was calculated to determine the validity of the clinometer app compared with goniometry. Main Outcome Measure: Degrees of motion for ankle plantar flexion. Results: Measurements produced using the Clinometer Smartphone Application™ were highly correlated for right foot (r = .92, P < .001), left foot (r = .92, P < .001), and combined (r = .92, P < .001) with goniometer measurements using a plastic universal goniometer. Conclusion: The Clinometer Smartphone Application™ is a valid instrument for measuring plantar flexion of the ankle.
Ken Pitetti, Ruth Ann Miller and E. Michael Loovis
Male youth (8–18 years) with intellectual disability (ID) demonstrate motor proficiency below age-related competence capacities for typically developing youth. Whether below-criteria motor proficiency also exists for females with ID is not known. The purpose of this study was to determine if sex-specific differences exist in motor proficiency for youth with ID. The Bruininks-Oseretsky Test of Motor Proficiency was used to measure motor proficiency: six items for upper limb coordination, seven items for balance, and six items for bilateral coordination. One hundred and seventy-two (172) males and 85 females with ID but without Down syndrome were divided into five age groups for comparative purposes: 8–10, 11–12, 13–14, 15–16, and 17–21 years. Males scored sufficiently higher than females to suggest that sex data should not be combined to established Bruininks-Oseretsky Test of Motor Proficiency standards for upper limb coordination, balance, and bilateral coordination subtests.
Zachary R. Weber, Divya Srinivasan and Julie N. Côté
The objectives of this study were to assess the sex-specific relationships between motor and sensory adaptations to repetitive arm motion–induced neck/shoulder fatigue, and to measure how additional sensory stimulation affects these adaptations. Twenty-three participants performed two sessions of a repetitive pointing task until scoring 8 on the Borg CR10 scale for neck/shoulder exertion or for a maximum of 45 min, with and without sensory stimulation (i.e., light touch) applied on the fatiguing shoulder. Just before reaching the task termination criteria, all participants showed changes in mean and variability of arm joint angles and experienced a fivefold increase in anterior deltoid sensory threshold in the stimulus-present condition. Women with the greatest increases in anterior deltoid sensory thresholds demonstrated the greatest increases in shoulder variability (r = .66), whereas men with the greatest increases in upper-trapezius sensory thresholds demonstrated the greatest changes in shoulder angle (r = −.60) and coordination (r = .65) variability. Thus, sensory stimulation had no influence on time to termination but affected how men and women differently adapted, suggesting sex differences in sensorimotor fatigue response mechanisms.
Karin Lobenius-Palmér, Birgitta Sjöqvist, Anita Hurtig-Wennlöf and Lars-Olov Lundqvist
This study compared accelerometer-assessed habitual physical activity (PA), sedentary time, and meeting PA recommendations among 102 youth with disabilities (7–20 years) in four subgroups—physical/visual impairments, intellectual disability, autism spectrum disorders, and hearing impairment—and 800 youth with typical development (8–16 years). Low proportions of youth with disabilities met PA recommendations, and they generally were less physically active and more sedentary than youth with typical development. The hearing impairment and autism spectrum disorder groups were the most and least physically active, respectively. Older age and to some extent female sex were related to less PA and more sedentary time. Considering the suboptimal levels of PA in youth with disabilities, effective interventions directed at factors associated with PA among them are needed.
Kelly P. Arbour-Nicitopoulos, Viviane Grassmann, Krystn Orr, Amy C. McPherson, Guy E. Faulkner and F. Virginia Wright
The objective of this study was to comprehensively evaluate inclusive out-of-school time physical activity programs for children/youth with physical disabilities. A search of the published literature was conducted and augmented by international expertise. A quality appraisal was conducted; only studies with quality ratings ≥60% informed our best practice recommendations. Seventeen studies were included using qualitative (n = 9), quantitative (n = 5), or mixed (n = 3) designs. Programs had a diversity of age groups, group sizes, and durations. Most programs were recreational level, involving both genders. Rehabilitation staff were the most common leaders. Outcomes focused on social skills/relationships, physical skill development, and psychological well-being, with overall positive effects shown in these areas. The best practice recommendations are consistent with an abilities-based approach emphasizing common group goals and interests; cooperative activities; mastery-oriented, individualized instruction; and developmentally appropriate, challenging activities. Results indicate that inclusive out-of-school time physical activity programs are important for positive psychosocial and physical skill development of children/youth with physical disabilities.
Tomomasa Nakamura, Yuriko Yoshida, Hiroshi Churei, Junya Aizawa, Kenji Hirohata, Takehiro Ohmi, Shunsuke Ohji, Toshiyuki Takahashi, Mitsuhiro Enomoto, Toshiaki Ueno and Kazuyoshi Yagishita
The aim of this study was to analyze the effect of teeth clenching on dynamic balance at jump landing. Twenty-five healthy subjects performed jump-landing tasks with or without teeth clenching. The first 3 trials were performed with no instruction; subsequently, subjects were ordered to clench at the time of landing in the following 3 trials. We collected the data of masseter muscle activity by electromyogram, the maximum vertical ground reaction force (vGRFmax) and center of pressure (CoP) parameters by force plate during jump-landing. According to the clenching status of control jump-landing, all participants were categorized into a spontaneous clenching group and no clenching group, and the CoP data were compared. The masseter muscle activity was correlated with vGRFmax during anterior jump-landing, while it was not correlated with CoP. In comparisons between the spontaneous clenching and the no clenching group during anterior jump-landing, the spontaneous clenching group showed harder landing and the CoP area became larger than the no clenching group. There were no significant differences between pre- and postintervention in both spontaneous clenching and no clenching groups. The effect of teeth clenching on dynamic balance during jump-landing was limited.
Matthew C. Hoch, David R. Mullineaux, Kyoungkyu Jeon and Patrick O. McKeon
Single joint kinematic alterations have been identified during gait in those with chronic ankle instability (CAI). The purpose of this study was to compare sagittal plane hip, knee, and ankle kinematics during walking in participants with and without CAI. Twelve individuals with CAI and 12 healthy individuals walked on a treadmill at 1.5 m/s. Three-dimensional kinematics were analyzed using mean ensemble curves and independent t tests. Participants with CAI demonstrated less lower extremity flexion during the absorption phase of stance and the limb placement phase of swing, which may have implications for limb placement at initial contact.
Bente R. Jensen, Line Hovgaard-Hansen and Katrine L. Cappelen
Running on a lower-body positive-pressure (LBPP) treadmill allows effects of weight support on leg muscle activation to be assessed systematically, and has the potential to facilitate rehabilitation and prevent overloading. The aim was to study the effect of running with weight support on leg muscle activation and to estimate relative knee and ankle joint forces. Runners performed 6-min running sessions at 2.22 m/s and 3.33 m/s, at 100%, 80%, 60%, 40%, and 20% body weight (BW). Surface electromyography, ground reaction force, and running characteristics were measured. Relative knee and ankle joint forces were estimated. Leg muscles responded differently to unweighting during running, reflecting different relative contribution to propulsion and antigravity forces. At 20% BW, knee extensor EMGpeak decreased to 22% at 2.22 m/s and 28% at 3.33 m/s of 100% BW values. Plantar flexors decreased to 52% and 58% at 20% BW, while activity of biceps femoris muscle remained unchanged. Unweighting with LBPP reduced estimated joint force significantly although less than proportional to the degree of weight support (ankle).It was concluded that leg muscle activation adapted to the new biomechanical environment, and the effect of unweighting on estimated knee force was more pronounced than on ankle force.