It has been suggested, that water exercise is less effective than weight-bearing exercise on land for body fat reduction.

To test this hypothesis 38 middle-aged obese women (25-47% body fat) participated in a 13 week exercise-diet program to compare the effects of aerobic exercise in water versus walking on land on indices of fat reduction and weight loss changes. Subjects were randomly assigned to 1 of 3 exercise groups:

1. walking on land (WL)
2. swimming (SW) at 27 degrees C water temperature
3. walking in 29 degrees C water (WW) at the shallow end of a declining pool with the water at navel height.

Subjects in the SW group alternated breast-, side-, and backstroke swimming without face immersion. Exercise parameters were kept constant for all three groups.

Subjects participated in supervised exercise sessions for 40 min, 4 times a week at 70% of age-predicted maximum heart rate.

Subjects were tested before and after the 13-week experimental period.

Significant reductions in body weight, (5.9 kg), percent body fat, (3.7%), and skinfold and girth measurements, occurred in all groups.

There where no significant differences between groups.

The results of this study indicate that there are no differences in the effect of aerobic activities in the water versus weight-bearing aerobic exercise on land on body composition components as long as similar intensity, duration and frequency are used.

References: PMID: 17119521