Advancing Performance: Biomechanics in Paralympic and Adapted Sports

IntroductionIn individuals with Cerebral Palsy (CP), both muscle cross-sectional area and fascicle length are reduced, contributing to decreased muscle strength, muscle shortening velocity and muscle mechanical power output, particularly in the plantarflexor muscles. A proposed mechanism to target increased muscle mechanical power output is to incorporate high velocity training (HVT) in these individuals, to increase fascicle length via sarcomerogenesis. To determine the effects of HVT on changes in MG muscle fascicle length and that impact on changes to MG muscle force-length-velocity-power characteristics in young adults with CP.Methods12 young adults with CP (GMFCS I or II, 22.8 ± 6.0 years) were randomly allocated (some crossover) to no training (CP-NT, n = 8), or training (CP-T, n = 8). 10 recreationally trained healthy adults (HA, 22.5 ± 2.8 years) served as controls. CP-T performed 10-week training of biweekly sessions consisting of progressive intensity 10 m sprints, plyometrics and agility tasks. Triceps surae muscle force-power-velocity relationships were quantified with isokinetic dynamometry and ultrasound imaging. Data are expressed relative to pre-intervention values.ResultsHVT resulted in a significant increase in fascicle length in CP-T (+1.92 ± 3.21 mm, p < 0.005) compared to a significant decrease in CP-NT (−1.63 ± 3.00 mm, p < 0.013). While HVT did not result in significant changes in maximal shortening velocity (Vmax) or maximal peak power output (Pmax), a large effect size for vmax following training in CP-T was seen (+45.2 ± 76.4%, d = 0.909, p = 0.452), in contrast to CP-NT (+2.9 ± 70.5%, d = 0.059, p = 1.00). HVT also resulted in a very large effect for Pmax in CP-T (+35.0 ± 49.1%, d = 1.093, p = 0.232), but only a small effect was observed in CP-NT (+7.8 ± 49.1%, d = 0.245, p = 1.00). HA had significantly greater Pmax (p < 0.001), longer resting and active fascicle lengths (p < 0.001) and greater muscle force (p < 0.001), compared to CP-T.DiscussionHVT is a feasible training intervention to increase triceps surae muscle fascicle length in individuals with CP. HVT can partially mitigate losses in Pmax in CP compared to healthy adults. Longer HVT programs may be required to increase muscle mechanical power output in CP to levels observed in HA.

The impact of pole position in seated shot put has been a key research question both in the previous literature and for coaches in the field. The aims of this research were to understand the dynamics of seated shot put and to investigate the impact of changing pole grip height on trunk parameters. Three grip heights are compared: the athlete's standard grip, 75 mm higher than standard, and 75 mm lower than standard, to determine which grip produced greater angular velocity and power at the trunk. In addition, a post-analysis intervention was implemented following this investigation where the athlete completed four weeks of training (8 sessions) with a grip height that was indicated to be superior. The trunk was found to provide the largest contribution to the movement, with a 64% of the total velocity contribution. A lower grip height was found to generate greater power and velocity in trunk rotation and flexion when compared to higher grip heights. When assessed over the intervention period, the lower grip height showed an increased rate of improvement throughout, and a performance advantage over the standard grip after just four sessions. This research demonstrates that pole grip height can impact athlete biomechanical parameters and may improve overall performance given sufficient time.