ACUTE EFFECTS OF PLYOMETRIC AND RESISTANCE TRAINING ON RUNNING ECONOMY IN TRAINED RUNNERS

Results regarding the acute effects of plyometrics and resistance training (PRT) on running economy (RE) are conflicting. Eight male collegiate distance runners (21 6 1 years, 62.5 +/- 7.8 ml . kg(-1) . min(-1) (V) over dot O-2 peak) completed (V) over dot O-2 peak and 1 repetition maximum (1RM) testing. Seven days later, subjects completed a 12 minutes RE test at 60 and 80% (V) over dot O-2 peak, followed by a PRT protocol or a rested condition of equal duration (CON). The PRT protocol consisted of 3 sets of 5 repetitions at 85% 1RM for barbell squats, Romanian deadlifts, and barbell lunges; the same volume was used for resisted lateral lunges, box jumps, and depth jumps. Subjects completed another RE test immediately after the treatments and 24 hours later. Subjects followed an identical protocol 6 days later with condition assignment reversed. Running economy was determined by both relative (V) over dot O-2 (ml . kg(-1) . min(-1)) and energy expenditure (EE) (kcal . min(-1)). There was a significant (p <= 0.05) between-trial increase in (V) over dot O-2 (37.1 +/- 4.2 ml . kg(-1) . min(-1) PRT vs. 35.5 +/- 3.9 ml . kg(-1) . min(-1) CON) and EE (11.4 +/- 1.3 kcal . min(-1) PRT vs. 11.0 +/- 1.4 kcal . min(-1) CON) immediately after PRT at 60% (V) over dot O-2 peak, but no significant changes were observed at 80% (V) over dot O-2 peak. Respiratory exchange ratio was significantly (p <= 0.05) reduced 24 hours after PRT (0.93 +/- 0.0) as compared to the CON trial (0.96 +/- 0.0) at 80% (V) over dot O-2 peak. Results indicate that high-intensity PRT may acutely impair RE in aerobically trained individuals at a moderate running intensity, but that the attenuation lasts less than 24 hours in duration.