PREDICTION OF ENERGY EXPENDITURE DURING SIMULATED ROCK CLIMBING

Abstract

PURPOSE: The primary purpose of this study was to characterize the energy cost of indoor climbing on a motor-driven climbing treadmill at different combinations of speed and grade. These data were then used to generate a prediction equation for submaximal oxygen consumption (VO2) for future applications. METHODS: Twenty “beginner” to “advanced” rock climbers (16 men, 4 women; Mean ± SD: 24.6 ± 4.2 yrs, 70.6 ± 7.4 kg) were recruited to climb on a motorized climbing treadmil (The RockTM with a 2.44 × 3.45 m climbing surface; Ascent Products, Inc., Bozeman, MT) at self-selected “slow” and “fast” climbing speeds at three different treadmill grades (vertical, defined as 90°; 85° or 80°; 95° or 100°). The 6 test conditions were each evaluated for 5 mins and separated by 2 mins of standing rest. VO2 was assessed using an Aerosport KB1-C portable metabolic system (2.04 kg) worn by subjects while climbing. Mean VO2 values were determined from the average of 1 min VO2 values over the last 3 mins of each 5-min test bout. Standard multiple regression procedures were used to generate an equation for predicting VO2 (dependent variable) from total mass of the climber and their clothing/equipment (Mass, kg), treadmill speed (SPD, m/min) and grade (GRD, degrees). RESULTS: The final VO2 prediction equation was as follows (R2 = 0.812; SEE= ± 0.164 1/min; n = 116 observations): VO2 (1/min) = 0.03221xMass + 0.1453xSPD + 0.02311xGRD −3.5301. Using the PRESS cross-validation technique, the R2 and SEE changed only slightly (0.792 and ± 0.170 1/min, respectively). CONCLUSIONS: The final regression equation was very accurate and stabile for predicting VO2 under these measurement conditions. The results from this study may be useful for certain exercise prescription applications or for predicting the physiological demands of treadmill climbing in future studies.