Physiological changes in sixth graders who trained to walk the Boston marathon.

The purpose of this study was to assess if supervised, low intensity training would improve aerobic capacity and body composition in sixth graders. Twelve sixth graders walk-trained at approximately 50% of their maximal heart rate, four to five days/week for 12 weeks; beginning with an average of 10 miles/week and increasing to about 27 miles/week (Experimental group [E]). Six subjects of similar age volunteered to be controls (Control group [C]). Baseline and post?training measurements included: height (cm), body weight (kg), sum of skinfolds at six sites (mm), and maximal oxygen consumption (VO2max; ml·kg(-1)·min(-1)). Three-day dietary records were also collected at pre-, mid-, and post-training to assess dietary changes that may have occurred during the study. There were significant increases (p < 0.05) from baseline to post-training in both groups in height and body weight. There was a significant interaction in the sum of skinfolds: E decreased 10.3% (p < 0.05) and C increased 2.3% (p > 0.05). There were no significant differences between groups in relative VO2max (ml·kg(-1)min(-1)) from baseline to post-training. C consumed significantly more total kilojoules (11,577 ± 3883 [C]; 7431 ± 2523 [E]) and more total grams of carbohydrate (392 ± 403 [C]; 227 ± 48 [E]) and fat (93 ± 97 [C]; 62 ± 29 [E]) than E, post-training. C also consumed significantly more total grams of protein than E pre-training (95 ± 99 [C]; 74 ± 21 [E]). In conclusion, walk-training elicited a significant decrease in sum of skinfolds with no change in relative VO2max. Furthermore, no dietary changes were observed in the experimental group as a result of the training.