This study compared the conventional track and a new one-handed track start in elite age group swimmers to determine if the new technique had biomechanical implications on dive performance. Five male and seven female GB national qualifiers participated (mean ± SD: age 16.7 ± 1.9 years, stretched stature 1.76 ± 0.8 m, body mass 67.4 ± 7.9 kg) and were assigned to a control group (n = 6) or an intervention group (n = 6) that learned the new one-handed dive technique. All swimmers underwent a 4-week intervention comprising 12 ± 3 thirty-minute training sessions. Video cameras synchronized with an audible signal and timing suite captured temporal and kinematic data. A portable force plate and load cell handrail mounted to a swim starting block collected force data over 3 trials of each technique. A MANCOVA identified Block Time (BT), Flight Time (FT), Peak Horizontal Force of the lower limbs (PHF) and Horizontal Velocity at Take-off (Vx) as covariates. During the 10-m swim trial, significant differences were found in Time to 10 m (TT10m), Total Time (TT), Peak Vertical Force (PVF), Flight Distance (FD), and Horizontal Velocity at Take-off (Vx) (p < .05). Results indicated that the conventional track start method was faster over 10 m, and therefore may be seen as a superior start after a short intervention. During training, swimmers and coaches should focus on the most statistically significant dive performance variables: peak horizontal force and velocity at take-off, block and flight time.
H. Galbraith, J. Scurr, C. Hencken, L. Wood and P. Graham-Smith
Ali Brian, Sally Taunton, Chelsee Shortt, Adam Pennell and Ryan Sacko
) in attempts to drive and sustain physically active behaviors ( Stodden et al., 2008 ). Most intervention studies in the United States that targeted young children from low socioeconomic environments are situated within Head Start facilities (i.e., federally funded early childhood centers for children
Kylie McNeill, Natalie Durand-Bush and Pierre-Nicolas Lemyre
impacted by effort, practice, and systematic interventions ( Durand-Bush et al., 2015 ; Schunk & Zimmerman, 2003 ). A series of intervention studies guided by the Resonance Performance Model (RPM; Dubuc-Charbonneau & Durand-Bush, 2015 ) have been conducted to examine the development of self
Chunxiao Li, Ngai Kiu Wong, Raymond K.W. Sum and Chung Wah Yu
cross-sectional design of the study limited the casual inferences of the results. Longitudinal surveys or intervention studies should be used in future to support the current ordering and interpretation. Third, although the current study extended the literature by including mindfulness as a predictor of
Lori Bolgla and Terry Malone
To provide evidence regarding the therapeutic effects of exercise on subjects with patellofemoral-pain syndrome (PFPS).
Evidence was compiled with data located using the Medline, CINAHL, and SPORTDiscus databases from 1985 to 2004 using the key words patellofemoral pain syndrome, exercise, rehabilitation, and strength.
The literature review examined intervention studies evaluating the effectiveness of exercise in subjects specif-cally diagnosed with PFPS. Articles were selected based on clinical relevance to PFPS rehabilitation that required an intervention of a minimum of 4 weeks.
The review supports using exercise as the primary treatment for PFPS.
Evidence exists regarding the use of isometric, isotonic, isokinetic, and closed kinetic chain exercise. Although clinicians have advocated the use of biofeedback and patella taping, there is limited evidence regarding the efficacy of these interventions on subjects diagnosed with PFPS.
John Manor, Elizabeth Hibberd, Meredith Petschauer and Joseph Myers
Rounded-shoulder and forward-head posture can be contributing factors to shoulder pain. Corrective techniques such as manual therapy and exercise have been shown to improve these altered postures, but there is little evidence that corrective garments such as posture shirts can alter posture.
To determine the acute effects of corrective postureshirt use on rounded-shoulder and forward-head posture in asymptomatic college students.
Repeated-measures intervention study with counterbalanced conditions.
24 members of the general student body of a university, 18–25 y old, with a forward shoulder angle (FSA) >52° and no history of upper-extremity surgery, scoliosis, active shoulder pain, or shoulder pain in the previous 3 mo that restricted participation for 3 consecutive days.
Photographic posture assessment under a control condition, under a sham or treatment condition (counterbalanced), under another control condition, and treatment or sham.
Main Outcome Measures:
FSA and forward head angle (FHA) calculated from a lateral photograph.
FSA decreased relative to the control condition while participants wore the sham shirt (P = .029) but not the corrective posture shirt (P = 1.00). FHA was unchanged between groups (P = .371).
Application of a corrective posture shirt did not acutely alter FSA or FHA, while application of a sham shirt may decrease FSA at rest.
Lukas D. Linde, Jessica Archibald, Eve C. Lampert and John Z. Srbely
Context: Females suffer 4 to 6 times more noncontact anterior cruciate ligament (ACL) injuries than males due to neuromuscular control deficits of the hip musculature leading to increases in hip adduction angle, knee abduction angle, and knee abduction moment during dynamic tasks such as single-leg squats. Lateral trunk displacement has been further related to ACL injury risk in females, leading to the incorporation of core strength/stability exercises in ACL preventative training programs. However, the direct mechanism relating lateral trunk displacement and lower limb ACL risk factors is not well established. Objective: To assess the relationship between lateral trunk displacement and lower limb measures of ACL injury risk by altering trunk control through abdominal activation techniques during single-leg squats in healthy females. Design: Interventional study setting: movement and posture laboratory. Participants: A total of 13 healthy females (21.3 [0.88] y, 1.68 [0.07] m, and 58.27 [5.46] kg). Intervention: Trunk position and lower limb kinematics were recorded using an optoelectric motion capture system during single-leg squats under differing conditions of abdominal muscle activation (abdominal hollowing, abdominal bracing, and control), confirmed using surface electromyography. Main Outcome Measures: Lateral trunk displacement, peak hip adduction angle, peak knee abduction angle/moment, and average muscle activity from bilateral internal oblique, external oblique, and erector spinae muscles. Results: No differences were observed for peak lateral trunk displacement, peak hip adduction angle, or peak knee abduction angle/moment. Abdominal hollowing and bracing elicited greater muscle activation than the control condition, and bracing was greater than hollowing in 4 of 6 muscles recorded. Conclusion: The lack of reduction in trunk, hip, and knee measures of ACL injury risk during abdominal hollowing and bracing suggests that these techniques alone may provide minimal benefit in ACL injury prevention training.
Zachary K. Winkelmann, Ethan J. Roberts and Kenneth E. Games
Context: Hamstring inflexibility is typically treated using therapeutic massage, stretching, and soft tissue mobilization. An alternative intervention is deep oscillation therapy (DOT). Currently, there is a lack of evidence to support DOT’s effectiveness to improve flexibility. Objective: To explore the effectiveness of DOT to improve hamstring flexibility. Design: Randomized single-cohort design. Setting: Research laboratory. Participants: Twenty-nine healthy, physically active individuals (self-reported activity of a minimum 200 min/wk). Interventions: All participants received a single session of DOT with randomization of the participant’s leg for the intervention. The DOT intervention parameters included a 1∶1 mode and 70% to 80% dosage at various frequencies for 28 minutes. Hamstring flexibility was assessed using passive straight leg raise for hip flexion using a digital inclinometer. Patient-reported outcomes were evaluated using the Copenhagen Hip and Groin Outcome Score and the Global Rating of Change (GRoC). Main Outcome Measure: The independent variable was time (pre and post). The dependent variables included passive straight leg raise, the GRoC, and the participant’s perceptions of the intervention. Statistical analyses included a dependent t test and a Pearson correlation. Results: Participants reported no issues with sport, activities of daily living, or quality of life prior to beginning the intervention study on the Copenhagen Hip and Groin Outcome Score. Passive straight leg raise significantly improved post-DOT (95% confidence interval, 4.48°–7.85°, P < .001) with a mean difference of 6.17 ± 4.42° (pre-DOT = 75.43 ± 21.82° and post-DOT = 81.60 ± 23.17°). A significant moderate positive correlation was identified (r = .439, P = .02) among all participants between the GRoC and the mean change score of hamstring flexibility. Participants believed that the intervention improved their hamstring flexibility (5.41 ± 1.02 points) and was relaxing (6.21 ± 0.86). Conclusions: DOT is an effective intervention to increase hamstring flexibility.
Nili Steinberg, Roger Adams, Oren Tirosh, Janet Karin and Gordon Waddington
Context: Ankle sprains are common among adolescent ballet dancers and may be attributed to inadequate ankle proprioception. Thus, a short period of training utilizing proprioceptive activities requires evaluation. Objective: To assess training conducted for 3 or 6 weeks on a textured-surface balance board using ankle proprioception scores for ballet dancers with and without chronic ankle instability, and with and without previous ankle sprain (PAS). Design: Intervention study. Setting: The Australian Ballet School. Participants: Forty-two ballet dancers, aged 14–18 years. Interventions: Dancers randomized into 2 groups: group 1 undertook 1 minute of balance board training daily for 3 weeks; group 2 undertook the same training for 6 weeks. Main Outcome Measures: Preintervention, Cumberland Ankle Instability Tool questionnaire data were collected, and PAS during the last 2 years was reported. Active ankle inversion movement discrimination ability was tested immediately pre and post intervention and at 3 and 4 weeks. Results: Ankle discrimination acuity scores improved over time for both groups, with a performance decline associated with the early cessation of training for group 1 (P = .04). While dancers with PAS had significantly worse scores at the first test, before balance board training began (P < .01), no significant differences in scores at any test occasion were found between dancers with and without chronic ankle instability. A significantly faster rate of improvement in ankle discrimination ability score over the 4 test occasions was found for dancers with PAS (P = .002). Conclusions: Three weeks of textured balance board training improved the ankle discrimination ability of ballet dancers regardless of their reported level of chronic ankle instability and at a faster rate for dancers with PAS. Previous ankle sprain was associated with a lower level of ankle discrimination ability; however, following 3 weeks of balance board training, previously injured dancers had significantly improved their ankle discrimination acuity scores.
Christian A. Clermont, Andrew J. Pohl and Reed Ferber
Context: The risk of experiencing an overuse running-related injury can increase with atypical running biomechanics associated with neuromuscular fatigue and/or training errors. While it is important to understand the changes in running biomechanics within a fatigue-inducing run, it may be more clinically relevant to assess gait patterns in the days following a marathon to better evaluate the effects of inadequate recovery on injury. Objective: To use center of mass (CoM) acceleration patterns to investigate changes in running patterns prior to (PRE) and at 2 (POST2) and 7 (POST7) days following a marathon race. Design: Pre–post intervention study. Setting: A 200-m oval track surface. Participants: Seventeen recreational marathon runners (10 females, age = 34.2 [5.67] y; 7 males, age = 47.41 [15.32] y). Intervention: Marathon race. Main Outcome Measures: An inertial measurement unit was placed near the CoM to collect triaxial acceleration data during overground running for PRE, POST2, and POST7 sessions. Twenty-two features were extracted from the acceleration waveforms to characterize different aspects of running gait. Lower-limb musculoskeletal pain was also recorded at each session with a visual analog scale. Results: At POST2, runners reported higher self-reported pain and exhibited elevated peak mediolateral acceleration with an increased mediolateral ratio of acceleration root mean square compared with PRE. At POST7, pain was reduced and more similar to PRE, with runners demonstrating increased stride regularity in the vertical direction and decreased peak resultant acceleration. Conclusions: The observed changes in CoM motion at POST2 may be associated with atypical running biomechanics that can translate to greater mediolateral impulses, potentially increasing the risk of injury. This study demonstrates the use of an accelerometer as an effective tool to detect atypical CoM motion for runners due to fatigue, recovery, and musculoskeletal pain in real-world environments.