Changes in skinfold thicknesses and body fat in ultra-endurance cyclists

The present study investigated the changes in single skinfold thicknesses and body fat during an ultra-endurance cycling race. One hundred and nineteen ultra-endurance cyclists in the 'Swiss Cycling Marathon' covering a distance of 600 km were included. Changes in skinfold thickness, fat mass, skeletal muscle mass and total body water were estimated using anthropometric methods. The subjects were riding at a mean speed of 23.5 +/- 4.0 km/h and finished the race within 1,580 +/- 296 min. During the race, body mass decreased by 1.5 +/- 1.2 kg [P<0.001], and fat mass decreased by 1.5 +/- 1.1 kg [P<0.001]. Skeletal muscle mass and total body water remained unchanged [P>0.05]. The decrease in body mass correlated to the decrease in fat mass [r = 0.20, P=0.03]. The skinfold thicknesses at pectoral [-14.7%], abdominal [-14.9%], and thigh [-10.2%] site showed the largest decrease. The decrease in abdominal skinfold was significantly and negatively related to cycling speed during the race [r = -0.31, P<0.001]. Cycling 600 km at 23 km/h led to a decrease in fat mass and in all skinfold thicknesses. The largest decrease in skinfold thickness was recorded for pectoral, abdominal, and thigh site. The decrease in abdominal skinfold thickness was negatively related to cycling speed. The body seems to reduce adipose subcutaneous fat during an ultra-endurance performance at the site of the thickest skinfold

Does muscle mass affect running performance in male long-distance master runners?

The aim of the present study was to investigate associations between skeletal muscle mass, body fat and training characteristics with running times in master athletes [age > 35 years] in half-marathon, marathon and ultra-marathon. We compared skeletal muscle mass, body fat and training characteristics in master half-marathoners [n=103], master marathoners [n=91] and master ultra-marathoners [n=155] and investigated associations between body composition and training characteristics with race times using bi- and multi-variate analyses. After multi-variate analysis, body fat was related to half-marathon [beta=0.9, P=0.0003], marathon [beta=2.2, P<0.0001], and ultra-marathon [beta=10.5, P<0.0001] race times. In master half-marathoners [beta=-4.3, P<0.0001] and master marathoners [beta=-11.9, P<0.0001], speed during training was related to race times. In master ultra-marathoners, however, weekly running kilometers [beta=-1.6, P<0.0001] were related to running times. To summarize, body fat and training characteristics, not skeletal muscle mass, were associated with running times in master half-marathoners, master marathoners, and master ultra-marathoners. Master half-marathoners and master marathoners rather rely on a high running speed during training whereas master ultra-marathoners rely on a high running volume during training. The common opinion that skeletal muscle mass affects running performance in master runners needs to be questioned

Participation and performance trends in triple iron ultra-triathlon - a cross-sectional and longitudinal data analysis

The aims of the present study were to investigate [i] the changes in participation and performance and [ii] the gender difference in Triple Iron ultra-triathlon [11.4 km swimming, 540 km cycling and 126.6 km running] across years from 1988 to 2011. For the cross-sectional data analysis, the association between with overall race times and split times was investigated using simple linear regression analyses and analysis of variance. For the longitudinal data analysis, the changes in race times for the five men and women with the highest number of participations were analysed using simple linear regression analyses. During the studied period, the number of finishers were 824 [71.4%] for men and 80 [78.4%] for women. Participation increased for men [r[2]=0.27, P<0.01] while it remained stable for women [8%]. Total race times were 2,146 +/- 127.3 min for men and 2,615 +/- 327.2 min for women [P<0.001]. Total race time decreased for men [r[2]=0.17; P=0.043], while it increased for women [r[2]=0.49; P=0.001] across years. The gender difference in overall race time for winners increased from 10% in 1992 to 42% in 2011 [r[2]=0.63; P<0.001]. The longitudinal analysis of the five women and five men with the highest number of participations showed that performance decreased in one female [r[2]=0.45; P=0.01]. The four other women as well as all five men showed no change in overall race times across years. Participation increased and performance improved for male Triple Iron ultra-triathletes while participation remained unchanged and performance decreased for females between 1988 and 2011. The reasons for the increase of the gap between female and male Triple Iron ultra-triathletes need further investigations

Predictor variables for marathon race time in recreational female runners

We intended to determine predictor variables of anthropometry and training for marathon race time in recreational female runners in order to predict marathon race time for future novice female runners. Anthropometric characteristics such as body mass, body height, body mass index, circumferences of limbs, thicknesses of skin-folds and body fat as well as training variables such as volume and speed in running training were related to marathon race time using bi- and multi-variate analysis in 29 female runners. The marathoners completed the marathon distance within 251 [26] min, running at a speed of 10.2 [1.1] km/h. Body mass [r=0.37], body mass index [r=0.46], the circumferences of thigh [r=0.51] and calf [r=0.41], the skin-fold thicknesses of front thigh [r=0.38] and of medial calf [r=0.40], the sum of eight skin-folds [r=0.44] and body fat percentage [r=0.41] were related to marathon race time. For the variables of training, maximal distance ran per week [r=-0.38], number of running training sessions per week [r=-0.46] and the speed of the training sessions [r=-0.60] were related to marathon race time. In the multi-variate analysis, the circumference of calf [P=0.02] and the speed of the training sessions [P=0.0014] were related to marathon race time. Marathon race time might be partially [r[2]=0.50] predicted by the following equation: Race time [min]=184.4+5.0 x [circumference calf, cm] -11.9 x [speed in running during training, km/h] for recreational female marathoners. Variables of both anthropometry and training were related to marathon race time in recreational female marathoners and cannot be reduced to one single predictor variable. For practical applications, a low circumference of calf and a high running speed in training are associated with a fast marathon race time in recreational female runners