An Ironman Triathlon Does Not Lead to a Change in Body Mass in Female Triathletes

Abstract

In 16 female nonprofessional Ironman triathletes, body mass, percent body fat, and skeletal muscle mass were determined before and after an Ironman race in order to detect changes. Selected hematological and urinary variables as well as percent total body water were measured in order to quantify a change in hydration status. Body mass, skeletal muscle mass, percent body fat, and percent body water did not change (p > 0.05). Plasma volume increased significantly by 8.1 (13.7) % (p < 0.05). The significant increase in plasma volume, plasma urea concentration, and urinary specific gravity after the race was associated with a significant fall in hematocrit and plasma sodium concentration (p < 0.05). In contrast to studies of male Ironman triathletes, we could not detect a decrease in body mass in female Ironman triathletes. The statistically insignificant loss of 0.6 kg in body mass was smaller than reported in studies of male athletes.

Changes in sex difference in swimming speed in finalists at FINA World Championships and the Olympic Games from 1992 to 2013

“…The lower skeletal muscle mass of female athletes compared to their male counterparts was argued to be another explaining factor of the lower sex difference with increasing race distance [28]. Already in 2010, Knechtle et al [29] reported that male ultra-endurance athletes have a higher skeletal muscle mass than female ultra-endurance athletes. Knechtle et al investigated the skeletal muscle mass of female and male Ironman triathletes [29] and ultra-runners [30].…”

“…Already in 2010, Knechtle et al [29] reported that male ultra-endurance athletes have a higher skeletal muscle mass than female ultra-endurance athletes. Knechtle et al investigated the skeletal muscle mass of female and male Ironman triathletes [29] and ultra-runners [30]. They reported that male triathletes had an approximately 46% higher skeletal muscle mass compared to their female counterparts.…”

Agreement between bioelectrical impedance and dual energy X-ray absorptiometry in assessing fat, lean and bone mass changes in adults after a lifestyle intervention

“…As the participants did not follow a unified/consistent dose of exercise, considerable heterogeneity/variability in the responses (fat and lean mass change) was expected, and this possibly inflated the LOA values. DXA is not a sufficiently adequate criterion method, but it is only a common reference (Bilsborough et al, 2014;Kyle et al, 2004a;Miyatani et al, 2012), and as not all measurements were taken by a single technician, but rather by qualified densitometrists using a standardised protocol, some variations in analysis might occur. Although BIA is predominantly used to estimate body water and fat mass, it is also now considered suitable to assess lean mass (Böhm & Heitmann, 2013;Bosaeus et al, 2014;Janssen, Heymsfield, Baumgartner, & Ross, 2000) and, recently, has also been used to predict bone mass in developing nations (Ekbote, Khadilkar, Chiplonkar, Mughal, & Khadilkar, 2013;Patil et al, 2012); yet, further work remains to further validate its use in predicting bone mass.…”

“…This uses 10 electrodes (3 under each foot, and 2 in each hand using a retractable handle), with a dual-frequency analysis at 6.25 and 50 kHz (Knechtle et al, 2010), to provide estimates of total (and segmental) lean mass, fat mass and bone mass. Participants were asked to refrain from vigorous physical activity, or consuming food, alcohol or diuretic fluids for 4 h beforehand, to be normally hydrated and were invited to void bladder and bowels immediately prior to measurement.…”

“…Consumer-based bioelectric impedance analysis (BIA) devices have become increasingly popular for selfmonitoring of body composition as they are often affordable, portable, safe and require no training for use (Kyle et al, 2004a(Kyle et al, , 2004b. Although studies often report extremely high levels of reliability for a range of BIA devices (Macfarlane, 2007), there is less agreement on their criterion validity.…”