Effects Of Morning Strength Training On Afternoon Countermovement Jump Performance In Collegiate Athletes

PURPOSE: Studies have examined the effects of various exercises, intensities, and volumes on subsequent neuromuscular performance tasks such as jumping and relevant to many practitioners is understanding whether there are delayed potentiation or fatigue effects under the common scenario in which an afternoon competition or practice occurs ~6 h after a morning strength training session. To compare the effect of a same-day resistance training session on countermovement jump (CMJ) peak power (PP), force at PP (FPP) and velocity at PP (VPP) between male and female collegiate athletes. METHODS: Twenty-four collegiate Division I male (n = 10, 19.2 ± .4 yrs, 76.6 ± 6.2 kg, 1.82 ± .08 m) and female (n = 15, 19.4 ± 1.1 yrs, 73.1 ± 8.4 kg, 1.74 ± .18 m) soccer and volleyball athletes completed two afternoon CMJ sessions (48 h apart). One session (random order) followed (4-6 h) a morning resistance training session (RTS), while the second occurred on a rest day. The RTS consisted of 2 sets of 10 repetitions of back squat, front squat, and forward lunge at 70-80% of their one repetition maximum. Five maximal effort CMJ trials (one min rest between trials), were completed on two force plates. Vertical ground reaction force data were used to compute jump height (JH), PP, FPP, and VPP. RESULTS: JH did not significantly change (P = .424, d = .04) between sessions for either the males (.006 ± .034 m) or females (.006 ± .037 m); however, the males jumped significantly higher (17.4%) than the females (P = .049, d = .72). Based on the interactions and main effects, there were no significant session effects for PP (P > .417), FPP (P > .700), nor VPP (P > .281). PP was significantly greater (P < .001, d = 1.6) for males (46.2 ± 3.2 W/kg) than females (39.0 ± 4.5 W/kg). FPP was significantly greater (P = .003, d = 1.2) for males (23.5 ± 2.4 N/kg) than females (20.8 ± 1.7 N/kg). There was no significant difference (P = .210, d = .44) between the males (1.99 ± .25 m/s) and females (1.88 ± .20 m/s) for VPP. CONCLUSIONS: that a morning RTS does not interfere nor enhance afternoon CMJ performance (JH), PP or the constituents of PP. Additional research should further evaluate CMJ strategies and joint kinetics.