Body composition in ultra running

nvestigated the change of body composition in ultra- endurance runners during a multi-stage ultra-endurance run, the Isarrun 2006 in Bavaria, Germany, where athletes had to run 338 km within 5 days. Body mass, skin fold thicknesses and circumferences of extremities were measured in 21 well- experienced extreme endurance male runners (mean ± SD, 41.5 ± 6.9 years, 72.6 ± 6.4 kg, 178 ± 5 cm, BMI 23.0 ± 2.0 kg·m -2 ), who finished mainly within the first half of the ranking, in order to calculate skeletal muscle mass and body fat mass to prove changes after the race. Body mass and calculated fat mass did not change significantly (p > 0.05), but, calculated skeletal muscle mass decreased significantly (p < 0.05) by 0.63 ± 0.79 kg by the end of the race. The most apparent decline (p < 0.01) of the calculated skeletal muscle mass was during the first stage, and no changes were observed during the last 4 stages. We conclude, that a multi-stage ultra-endurance run over 338 km within 5 days leads to no changes of body mass or body fat mass, but a statistically significant decrease of skeletal muscle mass of 0.63 ± 0.79 kg by the end of the race in well-trained and well-experienced ultra-endurance runners. The change of skele- tal muscle mass has to be evaluated in further studies at ultra- endurance races with suitable methods to detect changes in hydration status and water metabolism. Key words: Body composition, anthropometry, ultra-running, stage race, fat mass, ultra-endurance. Introduction It is well known that fat is the main energy-rich substrate for long lasting endurance performance (Frykman et al., 2003; Helge et

tal muscle mass has to be evaluated in further studies at ultra- endurance races with suitable methods to detect changes in hydration status and water metabolism. Key words: Body composition, anthropometry, ultra-running, stage race, fat mass, ultra-endurance. Introduction It is well known that fat is the main energy-rich substrate for long lasting endurance performance (Frykman et al., 2003; Helge et al., 2003; Raschka and Plath, 1992; Rey- nolds et al., 1999) and endurance exercise leads to a re- duction of adipose subcutaneous tissue as shown in labo- ratory (Boschmann et al., 2002) and field studies (Helge et al., 2003; Höchli et al., 1995; Raschka et al., 1991; Raschka and Plath, 1992). Ultra-endurance races are a good opportunity to study the decrease of adipose subcutaneous tissue in long lasting endurance performances. But there seems to be a difference between performances with defined breaks - for example during the night - and non-stop performances without defined breaks. In long lasting endurance per- formances with breaks such as multi-stage events, body mass may be stable (Cox et al., 2003; Dressendorfer and Wade, 1991; Nagel et al., 1989; Väänänen and Vihko, 2005) or even increase (Raschka and Plath, 1992) and body fat will be reduced (Cox et al., 2003; Raschka et al., 1991; Raschka and Plath, 1992) whereas skeletal muscle mass seems to be spared (Cox et al., 2003; Dressendorfer and Wade, 1991; Reynolds et al., 1999). In contrast, in ultra-endurance performances for hours or even days or weeks without a break, a decrease of body mass (Bircher et al., 2006; Helge et al., 2003; Knechtle et al., 2005; Lehmann et al., 1995) has been demonstrated, where body fat as well as skeletal muscle mass seems to decrease (Bircher et al., 2006; Knechtle et al., 2005; Knechtle and Bircher, 2005). Due to the fact, that up to now, the decrease of skeletal muscle mass in ultra-endurance performances has been demonstrated only in case reports (Bircher et al., 2006; Knechtle et al., 2005; Knechtle and Bircher, 2005) or small series (Helge et al., 2003), we wanted to investi- gate in this present study in a

al., 2005; Knechtle and Bircher, 2005). Due to the fact, that up to now, the decrease of skeletal muscle mass in ultra-endurance performances has been demonstrated only in case reports (Bircher et al., 2006; Knechtle et al., 2005; Knechtle and Bircher, 2005) or small series (Helge et al., 2003), we wanted to investi- gate in this present study in a greater sample of ultra- endurance athletes, whether ultra-endurance runners would suffer only a degradation of adipose subcutaneous tissue or whether they would experience an additional loss of skeletal muscle mass. In addition, we intended to quan- tify the loss of body fat mass and the loss of skeletal mus- cle mass. Method Subjects All participants of the Isarrun 2006 were contacted through a separate newsletter by the organiser 3 months before the race and asked to participate in the study. Sixty athletes (8 women, 52 men) intended to start. Fifty male and 7 female runners entered the race, 49 runners (6 women, 43 men) finished. Twenty-two white male Cau- casian runners entered the study. They all gave their in- formed written consent. From our subjects, 21 runners (values are given in mean ± SD; age 41.5 ± 6.9 years, weight 72.6 ± 6.4 kg, height 178 ± 5 cm, BMI 23.0 ± 2.0 kg·m -2 ) finished, mainly within the first half of the final ranking. One runner dropped out of the study group due to orthopaedic problems. The successful finishers trained for 11.6 ± 6.0 hours per week and had an average experi- ence of 7 ± 11 (2 to 50) finished races of 24 hours and longer prior the start of the actual race. The race The 3 rd Isarrun in Bavaria (Germany) took place from 15 th May to 19 th May 2006 over a distance of 338 km. Five stages (Table 1) had to be performed within 5 consecutive days. The limited field of 60 runners had to run from the delta of the Isar in Bavaria, Germany, as far as the source of the Isar in Austria. Athletes had their accommodation Research article

May to 19 th May 2006 over a distance of 338 km. Five stages (Table 1) had to be performed within 5 consecutive days. The limited field of 60 runners had to run from the delta of the Isar in Bavaria, Germany, as far as the source of the Isar in Austria. Athletes had their accommodation Research article

Body composition in ultra running 402 Table 1. The stages of the Isarrun 2006 with length and weather of each stage. Stage From – To Distance (km) Ascent (m)Descent (m) General weather conditions 1 Plattling – Dingolfing 62 280 230 Sunshine, dry, 22° Celsius 2 Dingolfing – Freising 75 240 145 Clouds, rain, 21° Celsius 3 Freising – Wolfratshausen 73 220 90 Sunshine, dry, 22° Celsius 4 Wolfratshausen – Fall 61 785 570 Moderate, 22° Celsius 5 Fall – Scharnitz 67 740 580 Moderate, 19° Celsius Total 338 2 265 1 615 in little hotel-restaurants in the towns for each stage of the run. Every morning at 07:00 a.m., the runners started the next stage together. No runner was allowed help from their personal support crew for the duration of each stage, and they had to run at least at a speed of 9 min·km -1 , oth- erwise they would be taken out of the race. Measurements and calculations The evening before the start and after arriving at the finish line every evening, body mass, circumferences of upper arm, thigh and calf were measured. Body mass was meas- ured with a commercial scale (Beurer BF 15, Beurer GmbH, Ulm, Germany) to the nearest 0.1 kg pre and post race while athletes were wearing the same clothes. Skin fold thicknesses and circumferences of the extremities were measured on the right side of the body, according to Lee et al. (2000). Circumference of the upper arm and calf were measured at the largest circumference of the limb; at the thigh 15 cm above the upper pole of the patella. All circumference measurements were recorded to the nearest 1 mm. Skin fold thicknesses of chest, midaxillary (verti- cal), triceps, subscapular, abdominal (vertical), suprailiac (at anterior axillary), thigh and calf were measured with a skin fold calliper (GPM-Hautfaltenmessgerät, Siber & Hegner, Zurich, Switzerland) to the nearest 0.2 mm. Every measurement was taken 3 times by the same person and then the mean value was used for calculation. Skeletal muscle mass (SM) was calculated using the following formula: SM = Ht x (0.00744 x

suprailiac (at anterior axillary), thigh and calf were measured with a skin fold calliper (GPM-Hautfaltenmessgerät, Siber & Hegner, Zurich, Switzerland) to the nearest 0.2 mm. Every measurement was taken 3 times by the same person and then the mean value was used for calculation. Skeletal muscle mass (SM) was calculated using the following formula: SM = Ht x (0.00744 x CAG 2 +0.00088 x CTG 2 ) + 0.00441 x CCG 2 + 2.4 x sex – 0.048 x age + race + 7.8, where Ht = height, CAG = skin fold-corrected upper arm girth, CTG = skin fold-corrected thigh girth, CCG = skin fold corrected calf girth, sex = 1 for male, race = 0 for white (Lee et al., 2000). Percent of body fat (%BF) was calculated using the following formula: %BF = 0.465 + 0.180(Σ7SF) - 0.0002406(Σ7SF) 2 + 0.0661(age), where Σ7SF = sum of skin fold thickness of chest, midaxillary, triceps, subscapular, abdomen, suprailiac and thigh mean (Ball et al., 2004). Fat mass was calculated with %BF from body mass. Statistical analysis Statistical analysis was performed with the R software package (R Development Core Team 2005). One sample Wilcoxon signed rank test were used to test for significant changes of body mass, skeletal muscle mass and fat mass during the complete Isarrun, during the first stage and during the last 4 stages. Bonferroni correction was used to compensate for multiple testing effects (3 pairwise tests of 3 parameters). For all statistical tests significance was set at the 0.05 level. Results Figure 1 shows the mean body mass, calculated body fat mass and calculated skeletal muscle mass before the Isar- run and after each of the 5 stages. Skin fold thicknesses and limb circumferences are shown in Figure 2 and Fig- ure 3. The day before the race started, body mass of the competitors ranged between 59.6 kg and 85.5 kg and did not change significantly (p > 0.05) during the Isarrun. Calculated fat mass ranged between 6.6 kg and 21.2 kg before the start. Even if there was a slight decrease of fat mass (p >

Figure 2 and Fig- ure 3. The day before the race started, body mass of the competitors ranged between 59.6 kg and 85.5 kg and did not change significantly (p > 0.05) during the Isarrun. Calculated fat mass ranged between 6.6 kg and 21.2 kg before the start. Even if there was a slight decrease of fat mass (p > 0.05) during the first stage, no significant de- crease is indicated during the complete Isarrun (p > 0.05). Skeletal muscle mass before the Isarrun started ranged from 34.3 kg to 46.1 kg and decreased significantly by the end of the Isarrun (p < 0.05) by 0.62 ± 0.79 kg (Figure 1). Decline of skeletal muscle mass was most apparent during the first stage of the Isarrun (p < 0.001) but did not change significantly (p > 0.05) during the following 4 stages. Discussion The main finding of our investigation is that a multi-day ultra-endurance run leads to a statistically significant decrease of skeletal muscle mass, whereas body mass and body fat mass remain stable. This is in contrast to the results of former ultra-endurance races and ultra- endurance performances with breaks where body mass remained stable (Dressendorfer and Wade, 1991; Nagel et al., 1989; Väänänen and Vihko, 2005), body fat was be reduced (Cox et al., 2003; Raschka et al., 1991; Raschka and Plath, 1992) and skeletal muscle was spared (Cox et al., 2003; Dressendorfer and Wade, 1991; Reynolds et al., 1999). Decrease of body mass during endurance performance Non-stop ultra-endurance races over hours and days, or even weeks, lead generally to a decrease of body mass (Bircher et al., 2006; Helge et al., 2003; Knechtle et al., 2005; Lehmann et al., 1995; Raschka, 1995; Volk et al., 2001). The decrease of body mass in these ultra- endurance athletes lies between 1.75 kg in a multi-day run over 1,000 km, 2 kg in an ultra-cycling race (Bircher et al., 2006), 2 kg in a Triple Iron triathlon (Volk et al.,

decrease of body mass in these ultra- endurance athletes lies between 1.75 kg in a multi-day run over 1,000 km, 2 kg in an ultra-cycling race (Bircher et al., 2006), 2 kg in a Triple Iron triathlon (Volk et al.,

Knechtle and Kohler 403 2001), 2.5 kg in a 6-day-run (Knechtle and Bircher, 2005), over 3.3 kg in a Double Iron Triathlon (Gastmann et al., 1998; Lehmann et al., 1995) to 5 kg in the Race across America (Knechtle et al., 2005). Figure 1. Body mass, calculated skeletal muscle mass and calculated fat mass during the Isarrun 2006. No standard deviations are included because they would exceed the displayed range. In order to keep multiple testing effects small only the most important time points were used for statistical analysis. The pair- wise comparisons are indicated in the figures by bars. * and *** indicate p < 0.05 and < 0.001. “ns” indicates no statistically significant differ- ence. In contrast to these results, our athletes in this ac- tual multi-stage ultra-endurance run showed no decrease of body mass, but interestingly, a significant decrease of skeletal muscle mass (Figure 1). In general, adipose sub- cutaneous tissue is the main energy source for long lasting endurance performances (Frykman et al., 2003; Raschka and Plath, 1992) and skeletal muscle mass seems to be spared (Reynolds et al., 1999). In very long lasting per- formances, body fat mass (Helge et al., 2003; Höchli et al., 1995; Knechtle and Bircher, 2005) as well as lean body mass (Bircher et al., 2006; Helge et al., 2003; Knechtle et al., 2005; Knechtle and Bircher, 2005) can decrease. In some situations – as described in case reports or studies with only a few subjects – skeletal muscle mass decreases in ultra-endurance performances (Bircher et al., 2006; Frykman et al., 2003; Helge et al., 2003). Decrease of fat mass in ultra-endurance performance In several studies, body fat decreases during ultra- endurance performance. In the study of Helge et al. (2003), where 4 male subjects crossed the Greenland icecap on cross-country skies, body mass decreased from 79.2 ± 3.9 kg to 73.6 ± 3.4 kg, the percentage of body fat decreased from 22.4 ± 1.4% to 18.2 ± 1.1% and the lean body decreased mass from 61.3 ± 2.0 kg to 60.3 ± 2.0 kg. On average, their subjects had a

where 4 male subjects crossed the Greenland icecap on cross-country skies, body mass decreased from 79.2 ± 3.9 kg to 73.6 ± 3.4 kg, the percentage of body fat decreased from 22.4 ± 1.4% to 18.2 ± 1.1% and the lean body decreased mass from 61.3 ± 2.0 kg to 60.3 ± 2.0 kg. On average, their subjects had a mean mass loss of 5.7 ± 0.5 kg, of which 78 ± 7% was fat and the remainder lean body mass. In a run over 1,000 km within 20 days, all skin fold thicknesses and the fat mass showed a falling tendency; only the thigh skin fold initially grew, and then came down from the 4 th day onwards (Raschka and Plath, 1992), and Höchli et al. (1995) could show at the Paris- Dakar Foot-Race over 8,000 km (600 km per runner within 30 days) a decrease of 10% body fat in their run- ners. Cox et al. (2003) demonstrated in a 1,049-mile sled dog race, that fat-free mass was maintained with a con- comitant decrease of body fat. In our subjects, body fat mass showed no decrease, but skeletal muscle mass de- creased statistically significantly by 0.62 ± 0.79 kg (Fig- ure 1). Figure 2. Skinfold thicknesses during the Isarrun 2006. Decrease of skeletal muscle mass in ultra-endurance performance Skeletal muscle mass seems to decrease in ultra- endurance races without breaks, as it has been shown in a few case reports (Bircher et al., 2006; Knechtle et al., 2005; Knechtle and Bircher, 2005) or a small series (Helge et al., 2003) of ultra-endurance athletes. In contrast, in other ultra-endurance performances, skeletal

Body composition in ultra running 404 muscle mass remained stable (Cox et al., 2003; Frykman et al., 2003; Reynolds et al., 1999). In a run over 1,000 km within 20 days, muscle mass initially decreased only from 59.3 kg to 58.9 kg on day 11 and increased at the end of the run to 59.9 kg, which was higher than the mus- cle mass at the start. As a result of the decreased muscle mass, all muscle circumferences were reduced with the exception of the thigh (Raschka et al., 1991). Figure 3. Means and standard deviations of the limb circum- ferences during the Isarrun 2006. Does dehydration lead to a loss of skeletal muscle mass in ultra-endurance performance? One problem in our study is the fact that we measured the athletes every day immediately after arriving at the finish line and could not determine correctly whether they were dehydrated or not. In all methods to determine body com- position it has to be considered that physical exercise and its effects on the body might influence measuring values, resulting in systematic errors of measurement. As it takes some time for the body to compensate for the dehydra- tion, the timing of measuring body mass after the race might also be of importance. Like dehydration, it takes some time for the body to compensate for the physical race effects. It must be hypothesized that the weight loss during an Ironman tri- athlon is mainly due to dehydration. Endurance perform- ance leads to dehydration, which results in a weight loss (Walsh et al., 1994). It is stated, though, that the weight loss in an Ironman triathlon derives most likely from sources other than fluid losses (Speedy et al., 2001). Many indices of hydration levels are known, such as body weight, plasma osmolality, urine osmolality and urine specific gravity (Kavouras, 2002). During dehydra- tion, we would generally expect an increase of haema- tocrit (Whiting et al., 1984). In contrast, ultra-endurance performance leads to a hypervolemia with haemodilution and a decrease of haematocrit (Astrand and Saltin, 1964; Davidson et al., 1987; Lindemann et al., 1978;

levels are known, such as body weight, plasma osmolality, urine osmolality and urine specific gravity (Kavouras, 2002). During dehydra- tion, we would generally expect an increase of haema- tocrit (Whiting et al., 1984). In contrast, ultra-endurance performance leads to a hypervolemia with haemodilution and a decrease of haematocrit (Astrand and Saltin, 1964; Davidson et al., 1987; Lindemann et al., 1978; Refsum et al., 1973; Wu et al., 2004). In a Triple Iron triathlon over 11.6 km swimming, 540 km cycling and 126.6 km run- ning, especially, haematocrit decreased from 48 ± 4% to 45 ± 3% (Volk and Neumann, 2001), 47.6 ± 3.0% to 43.1 ± 3.4% (Volk et al., 2001) and 48 % to 45 % (Volk et al., 1998) from pre race to post race. The phenomenon of hypervolemia with haemodilution and decrease of haema- tocrit is explained by a shift of intracellular water to the extracellular space and an increased fluid intake during performance (Wells et al., 1987). But the question still remains, whether dehydration really occurs during an ultra-endurance performance. There are studies at Ironman triathlons and Triple Iron triathlons showing that athletes suffer a loss of body mass without dehydration. Laursen et al. (2006) could demon- strate in their field-study with 10 Ironman triathletes, that the statistically significant decrease of 2.3 ± 1.2 kg (-3.0 ± 1.5%) body mass during the race was not related to urine specific gravity. Volk et al. (2001) examined, in the Triple Iron Germany 1999 in Lensahn, with bioimpedance analysis the hydration status in ultra-endurance triathletes. They compared their results of bioimpedance analysis with standard laboratory testing (haematocrit, serum os- molality and serum concentration of sodium). During the cycling part over 540 km, haematocrit increased from 45.6 ± 3.6% to 47.6 ± 3.0%, concentration of sodium decreased from 142.3 ± 1.0 mmol/l to 140.4 ± 2.3 mmol/l, plasma volume decreased by 5.8% and the cycling under hot conditions caused a steepening and lengthening of the vectors in the bioimpendance analysis. In contrast, after the following running part of 126 km in the heat, haema- tocrit decreased from 47.6 ± 3.0%

A study on body composition changes in ultra-endurance runners during a 338 km race.