The metabolic, hormonal, biochemical, and neuromuscular function responses to a backward sled drag training session

Abstract

We examined the metabolic, hormonal, biochemical, and neuromuscular function (NMF) responses to a backward sled drag training session (STS) in strength-trained men (n = 11). After baseline collection of saliva (testosterone and cortisol), whole blood (lactate and creatine kinase [CK]), and countermovement jumps (peak power output), participants completed 5 sets of 2 ×20-m (30 second-recovery between drags and 120 second-recovery between sets) maximal backward sled drags (loaded with 75% body mass). Participants were retested immediately, 15 minutes, 1, 3, and 24 hours after STS. Peak power output decreased after STS (baseline, 4,445 ±705 vs. 0 minute, 3,464 ±819 W; p = 0.001) and remained below baseline until recovering at both the 3-and 24-hour time points. No changes in CK levels were seen at any time point after STS. Blood lactate increased immediately after STS (baseline, 1.7 ±0.5 vs. 0 minute, 12.4 ±2.6 mmolL-1; p = 0.001) and remained elevated at 60 minutes (3.8 ±1.9 mmolL-1; p = 0.004) before returning to baseline at 3 and 24 hours. Testosterone peaked at 15 minutes post (baseline, 158 ±45 vs. 15 minutes, 217 ±49 pg ml -1; p <0.001) before decreasing below baseline at the 3-hour time point (119 ±34 pg ml-1; p = 0.008), but then increased again above baseline at 24 hours (187 ±56 pg ml-1; p = 0.04). Cortisol tended to increase at 15 minutes (baseline, 3.4 6 1.8 vs. 15 minutes, 5.2 ±2.7 ng ml-1; p = 0.07) before declining below baseline at 3 hours (1.64 ±0.93 ng ml-1; p = 0.012) and returning to baseline concentrations at 24 hours. In conclusion, sled dragging provides an effective metabolic stimulus, with NMF restored after #3 hours of recovery. Characterizing the recovery time course after sled training may aid in athlete training program design. © 2013 National Strength and Conditioning Association.