Work intensity during pedal-stepping exercise determined using a stair simulator based on vertical velocity / 体力科学

ABSTRACT

A study was conducted to ascertain the relationship between oxygen uptake (Vo<SUB>2</SUB>) and vertical velocity using a pedal-stepping stair simulator. Ten healthy volunteers performed fbur kinds of graded exercise using a stair simulator (SS), whose pitches were set at 80, 100, and 120 beat⋅min<SUP>-1</SUP>, and also an electrically braked bicycle ergometer (BE) . Work rate on the SS was detemined on the basis of the vertical pedal velocity, in accord with the climbingvelocity for stairs. The incremental rate was set at 0.34 W⋅kg<SUP>-1</SUP> every 3 min. Heart rate and Vo<SUB>2</SUB> were measured during the final minute of every stage. Both heart rate and Vo<SUB>2</SUB> during SS were significantly lower than those on BE at the same level of work intensity. Regression equations between Vo<SUB>2</SUB> (m<I>l</I>⋅kg<SUP>-1</SUP>⋅min<SUP>-1</SUP>) and velocity (<I>v</I> m⋅s<SUP>-1</SUP>) were as follows;<BR>pitch 80 Vo<SUB>2</SUB>=1.00×<I>v</I>+0.06<BR>pitch 100 Vo<SUB>2</SUB>=0.88×<I>v</I>+1.58<BR>pitch 120 Vo<SUB>2</SUB>=0.84×<I>v</I>+2.13<BR>These equations give a lower value of Vo<SUB>2</SUB> than the previous equation based on stair-climbingvelocity reported by the American College of Sports Medicine. Although the individual relationship between Vo<SUB>2</SUB> and heart rate was closely linear, there was a significant effect ofexercise mode and stepping pitch. These results indicate that the work intensity of pedalstepping exercise with a stair simulator is overestimated if it is calculated based on theprevious equation for stair-climbing.