Iron Experiment

Researcher

Marcia Myers and Karen Steudel U WI Zoology

Description

This study examined how the metabolic cost of locomotion varied with speed, stride frequency and body mass. Cost was determined by measuring oxygen consumption (vo2), analyzing the oxygen content in air inhaled and exhaled by the subjects through a mask. The rate of oxgen consumption was measured for three subjects locomoting at all combinations of low and high levels of the three factors --- running speed, stride frequency, and mass distribution in the leg. The first factor was set using a treadmill, the second by synchronizing the subjects' pace with a metronome, and the third by varying the positions of weights strapped onto the legs or waist. In addition to these three design factors, other variables were measured by filming each trial with a high-speed motion camera. Ignore these other measurements for this problem. The order of the eight combinations was randomly assigned for each test session. For each test combination, subjects continued running until their rate of oxygen consumption levelled off, between eight and 15 minutes into the run, signalling that steady state had been reached. Subjects were given daily sessions for an initial training period, during which the rate of oxygen consumption at each test combination decreased to a relatively constant level. Subjects were considered trained when their oxygen consumption for all test combinations were consistent and repeatable between test sessions. All subjects achieved the trained state within two weeks. The data used in this study were collected in single sessions from trained subjects. However, there still might be some concern about incomplete training causing systematic differences in consumption during the session.

Reference

Myers MJ, Steudel K and White SC (1993) `Uncoupling the correlates of locomotor costs: a factorial approach', J Experimental Zoology 265, 211-223.

Measurements

running.dat

subject order speed stride mass vo2 tm etot cn ar ecn ahm vhm

SAS Data Analysis

running.sas