Effects of Complex Training on Sprint Acceleration and Neuromuscular Performance in Young Male Sprinters: A Comparison Between Incline and Level Speed Bounding

PURPOSE: This study aimed to compare the effectiveness of complex training (CT) with inclined versus horizontal speed bounding on sprint acceleration ability and neuromuscular performance in youth male sprinters. METHODS: Thirty male sprinters 14 to 16 years of age were randomly allocated to 1 of 3 groups (n = 10/group): CT with incline speed bounding, CT with horizontal speed bounding, or control (CON). Both intervention groups completed 3 repetitions of back-squat exercise (85% 1-repetition maximum), followed by speed bounding on either a 9° or 0° platform, twice weekly for 6 weeks in addition to their usual training, whereas the CON group received no intervention. The 50-m sprint test, leg muscular power, isokinetic strength of knee extensors and flexors, and the Hoffman reflex and volitional wave in soleus and gastrocnemius muscles were measured before and after the intervention. RESULTS: Following 6 weeks of training, both the CT with incline speed bounding and the CT with horizontal speed bounding groups displayed similar improvements (P < .05) in 10- and 20-m sprint times compared with prior training and the CON group, of which the CT with incline speed bounding group showed a greater (P < .05) 10-m sprint velocity. These changes were concomitant with significant increases in peak force (P < .05) but not volitional wave amplitude and V:Mmax ratio in both muscles. However, the CON group did not show these improvements. CONCLUSION: These findings indicate that incorporation of inclined speed bounding into CT over 6 weeks is more effective in improving sprint acceleration performance compared with horizontal CT, irrespective with Hoffman reflex modulations.