Development and Reliability of Countermovement Jump Performance in Youth Athletes at Pre-, Circa- and Post-Peak Height Velocity

Abstract

The purpose of this study was to determine the intrasession reliability of countermovement jump (CMJ) braking and propulsive phase variables in youth athletes. Thirty youth athletes between the age of 10- and 16-years volunteered to take part in this study. All participants performance 3 CMJ trials on a force platform. Thirteen of 16 CMJ variables were found to have acceptable absolute reliability in the pre-PHV group (CV% = 3.51-9.96) whilst the circa-PHV group contained 10 variables demonstrating acceptable absolute reliability (CV% = 2.37-9.67). Almost all variables (14 out of 16) in the post-PHV group were found to have acceptable absolute reliability (CV% = 2.59-9.61). Mean and peak braking RFD displayed poor absolute reliability in all maturity groups (CV% = 10.89-21.55). Time to take-off, braking and propulsive phase time and propulsive impulse demonstrated the largest differences between pre- and circa-PHV groups (p < 0.005; d > 0.95). Braking phase time, peak and mean braking force, mean braking power and RSImod demonstrated the biggest differences between the circa- and post-PHV groups (p < 0.001; d > 1.81). The poorest reliability scores were found in the circa-PHV group, demonstrating the need for additional familiarisation at this stage of maturity.

Building for the Future: A Systematic Review of the Effects of Eccentric Resistance Training on Measures of Physical Performance in Youth Athletes

“…While de Hoyo et al [69] implemented 2 familiarisation sessions, Coutinho et al [44] did not report the inclusion of any familiarisation trials. Given the relatively unique mechanical demands of FIT, prior studies have recommended a minimum of 3 familiarisation trials for participants to become acquainted [48,80,81], which is likely even more important when working with children and adolescents [82,83]. Cumulatively, these reasons explain the differences in results from those of de Hoyo et al [69] and suggest that careful consideration regarding familiarisation prior to implementing FIT is crucial [48,84].…”

“…et al[83] To analyse the effect of an ERT programme on surrogate measuresof physical performance EXP: n = 18 male soccer participants, age = 18.0 ± 1.0 years CON: n = 15 male soccer participants, age = 17.0 ± 1.0 years Duration: 10 weeks, 1-2 sessions per week EXP group FIT exercises = prone leg curl and half squat (knee angle = 90°) EXP group progression: 1 session per week of 3 sets of 6 repetitions increasing to 2 sessions per week of 6 sets of 6 repetitions EXP and CON groups continued normal soccer-specific training (4-5 × 60-90 min sessions per week, plus 1 match) Pre-to post-intervention changes: EXP CMJ height = 7.6% (ES = 0.58), CON CMJ height = − 1.7% (ES = − 0.18) EXP 10 m sprint time = 1.0% (ES = 0.15), CON 10 m sprint time = − 0.3% (ES = − 0.05) EXP 20 m sprint time = 1.5% (ES = 0.32), CON 20 m sprint time = − 0.1% (ES = − 0.03) EXP 10 m flying sprint time = 3.3% (ES = 0.95), CON 10 m flying sprint time = 0.2% (ES = 0.05) The EXP group demonstrated greater improvements in surrogate measures of physical performance compared with the CON group de Hoyo et al [84] To analyse the effects of ERT on kinetic parameters during COD performance n = 31 male soccer participants, age = 17.0 ± 1.0 years Duration: 10 weeks, 1-2 sessions per week EXP group FIT exercises = prone leg curl and half squat (knee angle = 90°) EXP group progression: 1 session per week of 3 sets of 6 repetitions increasing to 2 sessions per week of 6 sets of 6 repetitions EXP and CON groups continued normal soccer-specific training (4-5 × 60-90 min sessions per week, plus 1 match) Pre-to post-intervention changes for crossover cutting at 60°: EXP CT = 9.1% (ES = 0.75), CON CT = 1.3% (ES = 0.09) EXP BT = 10.0% (ES = 0.35), CON BT = 3.3% (ES = 0.15) EXP PT = 4.2% (ES = 0.13), CON PT = 1.5% (ES = 0.09) EXP rPB force = 26.1% (ES = 0.75), CON rPB force = 31.5% (ES = 0.08) EXP rPF = 26.4% (ES = 1.34), CON rPF = 2.1% (ES = 0.07) EXP rTOT_IMP = 14.6% (ES = 0.61), CON rTOT_IMP = 3.1% (ES = 0.10) EXP rB_IMP = 22.4% (ES = 0.76), CON rB_IMP = 5.7% (ES = 0.16) EXP rP_IMP = 14.7% (ES = 0.46), CON rP_IMP = − 0.1% (ES = 0.00) Pre-to post-intervention changes for sidestep cutting at 45°: EXP CT = 17.7% (ES = 1.19), CON CT = 1.4% (ES = 0.08) EXP BT = 22.6% (ES = 1.24), CON BT = 6.5% (ES = 0.32) EXP PT = 13.6% (ES = 0.70), CON PT = − 0.5% (ES = − 0.03) EXP rPB force = 31.5% (ES = 0.75), CON rPB force = 8.0% (ES = 0.27) EXP rPF = 13.8% (ES = 0.68), CON rPF = 7.3% (ES = 0.23) EXP rTOT_IMP = 12.3% (ES = 0.48), CON rTOT_IMP = 2.2% (ES = 0.07) EXP rB_IMP = 14.8% (ES = 0.50), CON rB_IMP = − 1.7% (ES = − 0.06) EXP rP_IMP = 8.9% (ES = 0.26), CON rP_IMP = − 14.0% (ES = − 0.31) ERT led to greater braking and propulsive forces and impulses, and a lower braking and propulsive contact time during COD tasks…”

A Needs Analysis and Training Considerations for Female Adolescent Basketball Players

“…Vertical jump height can be assessed using a countermovement jump. The CMJ is considered a valid and reliable assessment measure for youth athletes (19,140). Several methods of evaluating a CMJ have been proposed, including .5 foot lifts (141) Balance and neuromuscular stability using a contact mat, force plates, and a vertec, with force plates demonstrating the greatest validity (23,95).…”