C.J. Alfiero, S.J. Brooks, C. Skiles, J. Bailey, A.F. Brown

University of Idaho, Moscow, ID

Research suggests that heavy resistance tasks (HRTs) potentiate skeletal muscle and increases power output during subsequent exercises, specifically during rapid, short duration movements such as countermovement jumps (CMJs) and sprinting. Few studies have demonstrated this potentiating effect in endurance sports (e.g., cycling and rowing), however, this phenomenon has not been investigated during endurance running. PURPOSE: To investigate the effects of pre-conditioning HRTs on ventilatory threshold 1 and 2 (VT1 and VT2) and maximal oxygen consumption (VO2max) during a graded exercise test (GXT) to volitional exhaustion on a treadmill. METHODS: Three recreational distance runners (age 24.3 ± 5.5 y, body mass 70.4 ± 3.6 kg, height 178.6 ± 3.9 cm) performed 4 GXTs following 3 different HRTs (sled-pull, sled-push, Bulgarian split-squat) and 1 exercise control (no pre- conditioning task). VT1 (concomitant rise in VE/VO2 and PETO2), VT2 (concomitant rise and fall in VE/VCO2 and PETCO2, respectively), and VO2max were measured using indirect calorimetry (Parvo Medics TrueOne 2400, Sandy, UT). Effect sizes (ES) and observed powers (OP; lower-bound) were calculated for VO2max, time-to-exhaustion, and time at VT1 and VT2 following each pre- conditioning task using a repeated measures analysis of variance. RESULTS: Mean VO2max values during the GXTs following the sled- push (SPs), sled-pull (SPu), split-squat (SS), and control (C) were 63.5 ± 7.9, 59.8 ± 8.4, 63.0 ± 6.5, 57.1 ± 10.2 ml∙kg-1·min-1 (ES = 0.787, OP = 0.338), respectively. Mean time-to-exhaustion values were SPs: 15.1 ± 0.9, SPu: 15.2 ± 1.6, SS: 15.4 ± 1.3, and C: 14.5 ± 1.2 min (ES = 0.732, OP = 0.272). Mean times at VT1 were SPs: 10.3 ± 1.8, SPu: 9.9 ± 1.9, SS: 9.9 ± 1.7, and C: 9.3 ± 1.7 min (ES = 0.838, OP = 0.427). Mean times at VT2 were SPs 13.2 ± 1.6, SPu: 12.2 ± 2.2, SS: 12.9 ± 2.5, and C: 11.9 ± 2.1 min (ES = 0.630, OP = 0.195). CONCLUSION: VT has been correlated with the onset of blood lactate accumulation and may be associated with endurance performance. The results observed in this pilot study suggest that pre-conditioning HRTs may delay the onset of VT1 and VT2 during a treadmill GXT. Future research will incorporate a true performance measure (e.g., time trial), and a larger sample size to achieve adequate statistical power.

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