Abstract

Prior high-intensity exercise has been shown to augment the oxidative energy contribution to subsequent exercise and enhance competitive performance. Inspiratory muscle training (IMT) is a form of resistance training for the muscles primarily involved in the processes of breathing using a resisted respiratory breathing trainer, which has also been shown to modify VO₂ kinetics and enhance performance. The potential impact of acute IMT as part of a warm-up on competitive performance, however, has not been investigated.

PURPOSE: To compare the effects of acute resisted IMT (EXP) to sham IMT (CON) as part of a warm-up on running performance.

METHODS: In a randomized cross-over design, 17 trained distance runners (age 20.1 ± 1.4 yr, body mass 62.2 ± 8.1 kg, height 1.73 ± 0.09 m) completed two 3200-m performance trials on separate days, preceded by two different warm-up procedures. Prior to each 3200-m trial, subjects performed a warm-up which consisted of a 20 min self-paced run and standardized mobility drills, followed by either EXP or CON in a randomized order and 4x 80m strides. Inspiratory muscle function was measured pre and post IMT. Heart rate (HR), rating of perceived exertion (RPE), rating of perceived dyspnea (RPD) and expired gases were collected using a metabolic analyzer during each trial.

RESULTS: 3200-m run performance was significantly faster after EXP (11.3 ± 1.1 vs. CON 11.8 ± 1.5 min, p = 0.01). Baseline inspiratory muscle function characteristics were not different between groups. Following each warm-up condition peak volume (EXP, 3.30 ± 0.85 vs CON 2.99 ± 0.68 L, p < 0.01), peak flow (EXP, 7.20 ± 1.77 vs CON 6.81 ± 1.73 L, p = 0.03), and peak strength index (EXP, 134 ± 39 vs CON 127 ± 34 cmH₂O, p = 0.03) were significantly higher after EXP. HR was not different between conditions (EXP, 183 ± 9 vs CON 182 ± 11), but VO₂ at each 800-m interval (EXP, 800-m 3.55 ± 0.65, 1600-m 3.63 ± 0.67, 2400-m 3.72 ± 0.70 vs CON 800-m 3.43 ± 0.66, 1600-m 3.54 ± 0.67, 2400-m 3.64 ± 0.70 L/min, p > 0.05) as well a peak VO₂ attained (EXP, 3.83 ± 0.73 vs CON 3.74 ± 0.76 L/min, p = 0.25) tended to be greater after EXP. RPE (EXP, 14.6 ± 1.1 vs CON 14.8 ± 0.9, p > 0.05) and RPD (EXP, 5.1 ± 1.2 vs CON 5.7 ± 1.6, p = 0.06) tended to be lower following EXP.

CONCLUSION: These data indicate that acute resisted IMT as part of a warm-up enhances 3200-m time-trial performance in trained runners.