Intraseason changes in the body composition of collegiate female gymnasts

Body composition measures were collected pre‐, mid‐ and post‐season on a team of eight national‐calibre collegiate women gymnasts to examine intraseason changes. Also analysed were interseason changes using pre‐ and post‐season data on five of the eight subjects during the current and previous year, according to a 2 x 2 (years x tests) analysis of variance repeated‐measures design. Skinfold, circumference and diameter measures were collected with percentage body fat, lean body mass and body density determined by regression equations developed specifically for collegiate female gymnasts.

Intraseason body weight decreased significantly from pre‐ to mid‐season (x = 55.0 and 53.6 kg respectively); but the difference between mid‐ and post‐season (53.9 kg) values was not significant (P>0.05). The majority of the 1.4 kg weight loss occurred during intense pre‐season conditioning and not during the actual season. Percentage body fat, on the other hand, decreased significantly from pre‐to mid‐season and mid‐ to post‐season (x = 21.4%, 17.4% and 13.45% respectively; P<0.0005). Body density increased significantly from pre‐ to mid‐season and mid‐ to post‐season (x = 1.0476, 1.0584 and 1.0681 respectively; P<0.0005). Of the circumference and skinfold values used in calculating percentage body fat and body density, only the skinfold values displayed significant decreases throughout the season.

Interseason analyses revealed no significant changes in any of the dependent measures between seasons, despite consistent trends. There were no significant years x tests interactions and all intraseason changes for two seasons (n = 5) were the same as those found in more detailed analysis of a single season (n = 8) except in the case of weight loss, which was marginally significant (P < 0.046) in the single‐season and not in the dual‐season analysis (P>0.05).

Body composition of these gymnasts changed in many ways within competitive seasons. The most pronounced changes observed were decreases in subcutaneous fat and increases in body density. This study reinforces the need for administrators, coaches and athletes to be concerned with percentage body fat and skinfold measures rather than weight alone when determining if a person is ‘fat’.     

Defensive Behaviors in Infant Rhesus Monkeys: Ontogeny and Context-dependent Selective Expression

We examined the ontogeny of the infant rhesus monkey's defensive behaviors and the ability to modulate them in response to specific environmental cues. Rhesus infants in 4 age groups (N = 8 per group) were briefly separated from their mothers and tested under 3 conditions: alone, in the presence of a human who averted his gaze, and in the presence of a human staring at them. Infants as young as 0 to 2 weeks displayed defensive behaviors but did not selectively respond to the human's presence or direction of gaze. By 9 to 12 weeks of age, infants modulated their responses in relation to the parameters of the threat. At this age, infant rhesus monkeys undergo cognitive and emotional changes associated with brain development similar to those in human infants 7 to 12 months old. This also is the time when human infants engage in complex emotional and behavioral responses to threatening situations. Understanding the development and expression of defensive behaviors in infant monkeys should be applicable to similar issues in emotional development of human infants.