Effects of Plyometric Training on Lower-Body Muscle Function in Novice Marathon Runners

Improvements in lower-body force production during concurrent endurance and explosive training have been reported in competitive runners, yet few studies investigate the effects of such training on muscle function in novice runners training for distances beyond 10,000 meters. PURPOSE: To investigate the impact of a plyometric training intervention on lower-body force and power production in novice runners training for a Marathon. METHODS: Students were recruited from a marathon training course. Participants were block randomized into two groups: plyometric/explosive speed training (PLYO) or core stability training (CORE). Squat jump (SJ) and counter-movement jump (CMJ) performance were evaluated using a force platform. Data were sampled at 1202Hz and filtered using a fourth-order Butterworth low-pass filter (50Hz). Dependent measures were peak force, average rate of force development (RFD), peak RFD and jump height, which were determined from the average of three jumps at the beginning and end of the 12-week intervention. A one-way analysis of covariance was conducted to discern between-group differences in jumping performance after the intervention. RESULTS: Vertical jump data were available for 20 participants (Mean ± SD: age = 20.4 ± 1.3 yr, height = 172.1 ± 9 cm, weight = 70.3 ± 10 kg, BMI = 23.5 ± 1.9 kg·m-2, 11 female). After adjusting for pre-intervention values, there was no significant difference between PLYO and CORE on post-intervention jump height during either SJ (p = 0.07, partial eta squared = 0.18) or CMJ (p = 0.57, partial eta squared = 0.02). Post-intervention values for peak force, average RFD and peak RFD did not differ between groups for either jump type. CONCLUSION: Jumping performance parameters were not affected by the 12-week PLYO intervention while concurrently training for a marathon. It appears that the high running volume associated with marathon training negatively influences the ability to increase lower-body force and power production in novice marathon runners. It is possible that one exposure per week of plyometric training performed after a 40-minute training run was insufficient to elicit adaptation in jumping performance. Future investigations should increase the frequency of plyometric training exposure and conduct this training before the days training run.