The Biomechanical Effects of Percussive Therapy Treatment on Jump Performance.

Percussive therapy treatment is one form of myofascial release that has gained popularity amongst the sport community. It has been suggested that percussive therapy treatment may improve range of motion and improve athletic performance, but these claims are largely anecdotal. Currently, the effects of percussive therapy treatment on performance of athletic tasks is relatively unknown. Therefore, the purpose of this research was to assess the effects of percussive therapy treatment on jump performance and passive range of motion. Twenty-six recreationally active college individuals performed countermovement jump and drop jump activities on two different days (one day with and one day without the use of percussive therapy treatment). Three-dimensional kinematics and kinetics were assessed during the jump activities. Passive range of motion was additionally assessed before and after warm up. A significant decrease in peak ankle eversion (2.0° during landing and 2.4° during take-off) was evident during the drop jump following the use of percussive therapy. All other frontal/sagittal plane peak joint angle and moment changes were nonsignificant. The hip and knee flexors and ankle extensors all showed increases in passive range of motion following treatment. Athletes who use percussive therapy treatment prior to physical activity will not have any adverse effects on performance or increased risk of injury. Muscles with lower levels of flexibility might be more susceptible to strain or injury. Percussive therapy treatment increased range of motion, which might help decrease the risk of injury.

Field Test Performance of Junior Competitive Surf Athletes following a Core Strength Training Program.

Lower body and core muscular strength are essential for optimal performance in many sports and competitive surfers have similar strength demands when maneuvering a surfboard to achieve competition success. Presently, the use of unstable surfaces is excessively utilized by surf coaches and trainers and to date, research does not support this as an effective training method for long-term improvements. Therefore, the purpose of this study was to determine the effectiveness of an 8-week Core Strength Training Program (CSTP) on a battery of field tests specific to assessing core musculature and lower body strength for junior competitive surf athletes. Nineteen American junior competitive surf athletes (age:15.7±1.01yrs, height:1.77±0.007m, mass:64.67±9.08kg) completed pre- and post-tests with a transitional pre-season to in-season 8-week CSTP intervention. The battery of tests included: rotational power (RP), time to peak acceleration (TP), maximal acceleration (Ma), maximal countermovement jump (CMJ), estimated peak power (PP), core strength (CS), core endurance (CE), and rotational flexibility (RF). Means, standard deviations, RMANOVA with a significance level of p < 0.05, and effect sizes were computed. Results demonstrated significant improvements in L.RP, TP, CMJ, PP, CS, and RF. Based on the results, the CSTP is an effective training program for surf coaches and strength and conditioning professionals to improve strength in the core musculature and lower body. In addition, we conclude implementation of the CSTP enhances athletic performance measurements which will likely increase competition success.

Anthropometry and barbell trajectory in the snatch lift for elite women weightlifters.

The primary objective of this study was to examine relationships between anthropometry and horizontal barbell displacement during the pulling phase of the snatch lift (SN) in elite women weightlifters. Secondary objectives included description of anthropometric and displacement characteristics, and examinations of SN performance and competitive experience. Thirty-six women weightlifters competing at the 2009 Pan American Championships participated. Participants were measured for standing height, upper limb, trunk, thigh, and shank lengths, and completed a questionnaire about competition and training experience. Horizontal displacement from lift-off to first pull maximum (Dx1) and from first pull to second pull maximum (Dx2) was determined from the heaviest successful SN using 2-dimensional video analysis. Significant correlations (p ≤ 0.05) existed between thigh and lower-limb lengths and Dx2 in 53 kg participants; lower-limb length and Dx1 in 75 kg participants; and horizontal displacement and body segment ratios involving the upper and lower extremity in multiple weight classes. Correlations between anthropometry and Dx1 also reached significance with participants grouped by barbell trajectory type. Except for the trunk and thigh, body segment lengths were significantly different (p ≤ 0.05) between weight classes. Significantly different body proportions existed in 48 kg participants compared with all other classes. Multiple thigh and trunk variables were significantly correlated with performance. Horizontal displacement values were similar to previous reports in the literature. Few significant relationships existed between displacement and performance, and none were found for competitive experience. Understanding relationships between anthropometry and barbell trajectory may be useful for optimizing SN technique.

Effects of delayed onset muscle soreness on selected physiological responses to submaximal running.

This study examined the effects of delayed-onset muscle soreness (DOMS) on selected physiological responses to submaximal exercise. Seven male and four female subjects (Ss) aged 21-37 years completed two submaximal running sessions at an individualized pace corresponding to a blood lactate concentration (bLa) of approximately 2.5 mmol x L(-1). Following the first session (T1), Ss performed a series of lower extremity resistance exercises designed to induce DOMS. Subjects were then retested (T2) 24-30 hours later, during which time all Ss experienced DOMS. Oxygen uptake, heart rate (HR), respiratory exchange ratio, rating of perceived exertion (RPE), and bLa were measured every 6 minutes. Significant trial effects (p < 0.05) were observed for HR and RPE. HR was significantly higher during T1 at minutes 6 and 12 (p < 0.05), and RPE values were significantly higher at T2 during all recording periods (p < 0.05). Results from this study suggest that DOMS does not affect submaximal oxygen uptake. However, DOMS does appear to affect one's perception of effort.