Metabolic Cost Of Resistance Exercise

Abstract

PURPOSE: Determine if the Total O2 cost (TO2) of RE differs during & following RE as a function of RE type & relative intensity (RI) & Determine if TO2, during & following RE, differs across 3 RI, when the volume of Work is held constant. METHODS: 8 Ss, 6 female, volunteered. Ss underwent testing for VO2Max, body composition, & 1-RM for Chest Press (CP) & Leg Press (LP). RI were 33, 50, & 75% 1-RM, with 22, 15, & 10 reps performed, respectively to control for volume of work during RE. RE consisted of: 5min Rest, followed by RE, & 10min Post RE Rest; RE & Post RE Rest were repeated for RE type (LP & CP) & RI. RE & RI were counterbalanced. Metabolic measures & HR were recorded using a Cosmed K4b2. Body composition was measured with BodPod. RESULTS: Age=21.5±0.5, Height=166.5±6.2, Mass=65.4±11.7, BMI=23.5±3.7, BodyFat%=20.7±7.5, FatMass=13.8±7.5, LeanMass=51.5±7.7, VO2max=46.4±8.4, RERmax=1.13±0.03, & HRmax=200±6.2. TO2 cost was measured as the O2 used during exercise & through 10 min Post RERest using Integral estimation of breath-by-breath intervals. TO2 cost during RE & 10 min Post RE Rest was significantly greater for LP when compared to CP at each corresponding RI: LP75-CP75 p=0.005, CI95%(6.72,13.58); LP50-CP50 p=0.003, CI95%(4.12,13.98); LP33-CP33 p=0.005, CI95%(1.81,7.33). TO2 cost was significantly (p<0.02) greater for LP75 & LP50 when compared to LP33. TO2 cost for CP was not significantly different at any RI. LP & CP RE times differed significantly for RI: LP75-50 p=0.000, LP75-33 p=0.001, LP50-33 p=0.016, CP75-50 p=0.007, CP75-33 p=0.000, CP50-33 p=0.002. TO2 cost for LP75 & CP75 returned to Pre RE Rest at min 3. CONCLUSIONS: Results suggest TO2 cost is related to RE type, muscle mass activated, O2 deficit incurred during RE, & O2 debt repaid during recovery. Further, the O2 cost during recovery from LP75 & LP50 is greater when compared to LP33 even though Work was held constant. This suggests factors other than the O2 deficit contribute to the O2 debt.