Determinants Of Metabolic Cost During Four Styles Of 30-second Sprint Rope Skipping

Abstract

Rope jumping has been a major training tool for many sports. However, no study has been conducted as yet to determine energy expenditure with incremental skipping rate per jump (difficulty) from single under to quad under. PURPOSE: To determine and compare 30-seconds all-out effort energy expenditure between four incremental rope skipping difficulties. METHOD: Ten skilled rope-jumpers (height=169.3±4.7cm, body mass=65.5±9.2kg, age=23.2±2.1yrs, years of training=3.8±1.3yrs) volunteered to participate this study. Participants conducted rope skipping as many repetitions as possible at 1 skip.jump-1 (single under, SU), 2 skips.jump-1 (double under, DU), 3 skips.jump-1 (triple under, TU) and 4 skips.jump-1 (quad under, QU) during 30-second test with 24 hours between trials. Kinematic and kinetic data were collected to calculate flight time (FT) and vertical center of mass displacement (vCOM). Each style was assessed in three trials and then averaged. Net energy expenditure (Wtot) was calculated from VO2 during exercise, the fast component of the EPOC above resting and net blood lactate production. RESULT: SU exhibited significantly lower VO2peak (28.01±4.62 ml.kg-1.min-1, p<0.05) compared to TU (34.96±3.45) and QU (36.12±6.38). Wtot (J.jump-1) in QU (7975.1±3265.66 J.jump-1) was significantly higher than these values of the other three styles (SU 474.9±108.80, DU 1086.4±183.17, TU 1769.3±540.46, p<0.05). FT (ms) and vCOM (cm) increased significantly with increase in difficulty (SU: 125.0±19.6 and 1.95±0.66, DU: 276.6±36.1 and 9.53±2.24, TU: 473.6±32.1 and 27.64±3.76, QU: 544.4±60.5 and 36.76±8.15, p<0.01). 30s skip repetitions in QU (46.0±19.34) was significantly lower than the other styles (SU 105.2±12.08, DU 128.2±15.12, TU 126.9±20.39, p<0.01). Standard Wtot (J.kg-1.jump-1) was exponentially related to skipping difficulty from 1 skip.jump-1 to 4 skips.jump-1 (R2=0.89, p<0.001). CONCLUSION: Skipping difficulty (skip per jump) is one of the main determinants of metabolic cost, whereas skip repetition does not significantly contribute to metabolic cost during 30 seconds all-out rope skipping.