Abstract

Intensive strength-training (ST) can result in exercise induced muscle damage (EIMD), which commonly leads to reductions in acute muscle function. Post-exercise ingestion of carbohydrate and protein mixtures attempt to attenuate the effects of EIMD. This study aimed to compare the effectiveness of whey-protein-hydrolysate and milk-based formulated drinks on recovery of muscle function following ST. Thirty resistance-trained males (age: 25.2 ± 5.5 years, mass: 79.4 ± 8.4 kg, stature: 1.77 ± 0.45 m) provided written informed consent to participate. The study was approved by the local ethics committee inline with Helsinki Declarations. Participants were randomly equally assigned to either; whey-hydrolysate and dextrose drink (WH), milk-based drink (MB), flavoured dextrose (PLACEBO) and performed baseline assessments of perceived muscle-soreness (SORENESS), static-squat jump (SSJ), countermovement jump (CMJ), seated medicine-ball throw (MBT) and isokinetic assessments of the knee-extensors and flexors. Subsequently, participants performed a ST session consisting of various multi-joint barbell exercises. Participants then consumed either WH, MB or PLACEBO 10 min following ST, subsequently repeating all assessments 24 h and 48 h post-ST. In relation to within-group changes, all groups experienced substantial increases in SORENESS at 24 h and 48 h (P < 0.001). However, for dynamic power measures (SSJ, CMJ and MBT), PLACEBO experienced a decrease for only CMJ at 48 h (−1.8 cm), whereas WH and MB experienced significant decreases across SSJ (WH; −3 cm at 24 h, MB; −2.6 cm at 24 h, −2.0 cm at 48 h), CMJ (WH; −2.4 cm at 24 h, MB; −3.7 cm at 24 h, −3.3 cm at 48 h) and MBT (WH; −0.25 m at 48 h, MB; −0.33 cm at 24 h, −0.38 m at 48 h) (P < 0.05). All groups experienced significant decreases in isokinetic-extension torque at both 24 h and 48 h; however, flexion torque was decreased for PLACEBO only at these time points (24 h: −10 N · m, 48 h: −13 N · m) (P < 0.05). Isokinetic-extension power and work were significantly decreased at 24 h and 48 h for both WH [Power (24 h: −18 W, 48 h: −13 W) Work (24 h: −30 J, 48 h: −22 J)] and PLACEBO [Power (24 h: −15 W, 48 h: −14 W) Work (24 h: −25 J, 48 h: −28 J)] (P < 0.05); however, no decreases occurred for MB. Flexion power was significantly decreased for only PLACEBO at 24 h and 48 h (24 h: −7 W, 48 h: −6 W) (P < 0.05). Decreases in flexion work occurred across all conditions at 48 h, but only for PLACEBO at 24 h (WH, 48 h: −6 J) (MB, 48 h: −15 J) (PLACEBO, 24 h: −11 J, 48 h: 13 J) (P < 0.05). Consumption of WH or MB had no effect on recovery of dynamic power-producing ability or soreness compared to PLACEBO. However, WH and MB seemingly had positive effects on recovery of isokinetic muscle-function.