The effect of four weeks of plyometric training on reactive strength index and leg stiffness is sport dependent

Abstract

BACKGROUND: Plyometric exercises are often used to develop lower limb strength and performance-related biomechanics such as leg stiffness. However, the effectiveness of plyometric training may depend on participants' own training and performance demands. The purpose of this study was to examine the effect of plyometric training on reactive strength index (RSI) and leg stiffness (Kleg) on young athletes of different sports. METHODS: Forty eight female athletes (25 Taekwondo (TKD) & 23 rhythmic gymnastics (RG), mean ± SD: age: 8.94 ± 2.50 years; mass: 29.73 ± 7.69 kg; height: 138.84 ± 11.90 cm; training experience: 4.62 ± 2.37 years) participated in this study.Participants were randomly assigned to experimental (PT, N = 24) and control (CG, N = 24) groups. The PT group followed a twice-weekly plyometric training program for 4 weeks. Plyometric drills lasted approximately 5-10 s, and at least 90 s rest was allowed after each set. To examine RSI, participants performed trials of five maximal CMJs. Submaximal hopping (20 hops) was performed in order to examine leg stiffness. RESULTS: Significant interaction effect was found for RSI and the post hoc analysis showed that RSI significantly increased by 35% (p = 0.017) in RG athletes, whereas a significantly reduction by 28% (p = 0.004) was revealed in TKD athletes. The interaction effect between time and group was statistically significant for Kleg (p < 0.05) with Kleg significantly increasing by 31% (p = 0.008) in TKD athletes, but remaining unchanged (p > .05) in RG athletes. CONCLUSIONS:The results showed that the effect of a 4-week plyometric training program on RSI and leg stiffness is sport dependent. Further, the applied plyometric program was effective in reducing ground contact time and therefore increasing leg stiffness.

The Effect of 6-Week Combined Balance and Plyometric Training on Change of Direction Performance of Elite Badminton Players

“…RSI is an indicator of how efficiently athletes perform the SSC. Although plyometric training has been shown to significantly improve the efficiency of SSC utilization (Jeffreys et al, 2019;Dallas et al, 2020), it is interesting to note that the BP group exhibited a greater increase in RSI. A potential reason could be that balance training enhanced the body control of players and finally reduced the time spent on the landing during jumps.…”

Effects of jump training on physical fitness and athletic performance in endurance runners: A meta-analysis

“…The observed improvements in reactive strength indices were an expected finding of this SRMA. Surprisingly, however, this outcome is in contradiction to the absence of an effect of JT on stiffness measures, as reactive strength indices are supposedly proxies of neuromuscular stiffness (Dallas et al, 2020;Flanagan & Comyns, 2008;García-Pinillos et al, 2020b;Li, Newton, et al, 2019a;Markovic & Mikulic, 2010). This finding may be related to the limited number of studies which included different measures of stiffness (five vs. eight studies for stiffness and reactive strength, respectively), and the variety of methods and indices used.…”

The Effect of 16 Weeks of Lower-Limb Strength Training in Jumping Performance of Ballet Dancers

“…Other studies also showed significant improvements in the jumping performance of dancers (Wang et al, 2010;Komeroski et al, 2016;Tsanaka et al, 2017;Escobar-Alvarez et al, 2019;Stošić et al, 2020) and rhythmic gymnasts (Piazza et al, 2014;Dobrijević et al, 2018;Dallas et al, 2020) as a result of training interventions, and the improvements in jumping performance are consistent with previous findings in ballet dancers (Escobar-Alvarez et al, 2019;Alvarez et al, 2020) and in other sports disciplines (Jimenez-Reyes et al, 2016, Jiménez-Reyes et al, 2019. We suggest an exercise prescription based on the individual needs and the physical demands of ballet, jazz, and contemporary dancers as referred to in previous studies (Alvarez et al, 2020;Dowse et al, 2020).…”