Associations Between Body Composition and Performance in Elite Endurance Athletes

Purpose : To investigate if elite endurance athletes periodized their body mass (BM) and composition from preparation (T 1 ) to specific preparation period (T 2 ) and if changes in BM and body composition were associated with improved endurance performance. Methods : Fifty-two elite endurance athletes participated in this study. Thirteen cross-country skiers, 7 biathletes, and 3 Nordic Combined athletes formed a group of skiers (16 men and 7 women), and 5 endurance runners, 22 orienteers, and 2 triathletes formed a group of runners (17 men and 12 women). Anthropometric (dual-energy X-ray absorptiometry) and performance (sport-specific incremental treadmill test) measurements were completed in T 1 and T 2 . Results : No changes in BM or body composition were detected from T 1 to T 2 except for lean mass (LM), which increased in only runners ( P = .03). Peak running speed (V peak ; P < .001) and relative peak oxygen uptake ( P = .04) increased from T 1 to T 2 regardless of the sport or sex. Decreased body fat mass and percentage were associated with increased V peak ( r = −.41, P = .002; r = −.45, P < .001) and relative peak oxygen uptake ( r = −.31, P = .03; r = −.32, P = .02). Changes in LM were positively associated with changes in V peak in female skiers ( r = .80, P = .03), while almost all the female runners increased both LM and V peak . Conclusions : Elite endurance athletes did not systematically periodize their BM from T 1 to T 2 . Decreases in body fat mass and percentage may be beneficial for endurance performance. Since increases in LM were associated with improved endurance performance in female athletes, body-composition manipulations should not lead to a decrease in LM.