Metabolic Cost Comparison Between Submaximal Land (TM) And Aquatic (ATM) Treadmill Exercise

Abstract

Aquatic exercise may be necessary as adjunct training in athletes restricted from land training due to symptoms of overuse injuries. PURPOSE: Compare the metabolic cost of land (TM)vs aquatic (ATM) treadmill exercise. METHODS: Fifteen subjects (7 male, 8 female, age = 22±4 yr, 173±8 cm, 66.9±9 kg) completed: 1) nine, 5 min submaximal ATM exercise trials at 174, 201, & 228 m-min-1 treadmill (Hydroworx®) speeds, while submerged to the xiphoid process with water jet resistances (directed at torso) set at 0, 50 & 75% of jet capacity. The corresponding land TM speeds which yielded VO2 costs similar to ATM conditions (starting with ACSM prediction equations and adjusting 2.68 m-min-1) were experimentally determined. VO2, VE, HR, and O2 pulse were recorded during mins 3–5 and averaged for each trial. RESULTS: During ATM, increasing running speed and water jet resistance both significantly increased VO2, HR, VE, O2 pulse, and RPE. When corresponding land TM speeds were determined, there were no significant differences in land TM speed versus ATM with 0% jet resistance. Adding 50 and 75% jet resistance to ATM speeds increased the land TM required to elicit a similar metabolic cost by 27.8 and 54.6 m-min-1, respectively (Table 1).TableTable 1. VO2 (ml- kg-1- min-1 X±SD) for TM speeds (m-mirr1) and ATM conditions (speed/jet resistance) CONCLUSIONS: These results suggest the ATM yields similar metabolic costs to land TM within running speeds of 174–228 m-min-1. The additional resistance provided by water jets provides further demands that may serve as an appropriate exercise training stress (similar to running at ∼268 m-min-1 on land) for most subjects who require time off from normal land workouts.