Body Composition and Somatotype of Experienced Mountain Climbers

Introduction

The study of the human form in sports may be a useful tool to monitor and evaluate the effectiveness of a training protocol, or for early talent discovery. In fact, type, intensity, and volume of physical activity affect some anthropometric characteristics, such as body weight, muscle mass, and body fatness. At the same time, some anatomic traits are genetically determined (e.g., height and bone breadth) and may be more or less favorable to sport excellence. Thus, anthropometry accounts for both trainable and nontrainable performance factors.

Several studies have been dedicated to determine the athletes' body composition and the dominant somatotype in different sports (Carrasco et al., 2010; Claessens et al., 1999; Cortell-Tormo et al., 2010; Gualdi-Russo and Zaccagni, 2001; Rienzi et al., 2000; Sterkowicz-Przybycien, 2009).

Although a wealth of studies on free climbers exists (Cheung et al., 2011; Draper et al., 2008; España-Romero et al., 2009; Grant et al., 1996; Mermier et al., 2000; Morrison and Schöffl, 2007; Sheel, 2004; Watts et al., 2003), there is a dearth of research on somatotype and body composition of mountain climbers (Bales et al., 1993; Egocheaga et al., 1998; Zamboni et al., 1996). Therefore, the relationship between this sport, body composition, and somatotype is worth being investigated further.

Mountain climbing is becoming a popular sport, requiring intense physical activity, especially walking across long distances, at high altitude, low temperature, in hypobaric and hypoxic conditions, often carrying heavy rucksacks.

In the present study, we take into consideration the anthropometric characteristics—in particular, body composition and somatotype—of a sample of Italian experienced mountain climbers, and we compare them with athletes involved in other climbing activities, using data taken from the literature on the subject.

Materials and Methods

The study was carried out on 10 male Italian climbers, aged 41.4±5.5 (mean±SD), training experience 21.0±4.8 years, weekly training hours 24.1±11.7. The climbers were assessed a month before the beginning of the “K2 2004—50 years later” expedition to the north face of Mt. Everest and they all had previous experience of climbing in the Himalayas. Subjects gave their informed consent to the study, which was approved by the scientific board of the Istituto Nazionale della Montagna (Italian Mountain Institute, Rome, Italy).

The same sample was also studied from the perspective of ventilation by Bernardi et al. (2006) and from the perspective of metabolic and endocrine responses by Benso et al. (2007).

The subjects, in underwear and barefoot, were evaluated by means of standardized anthropometric procedures (Lohman et al., 1988). A properly trained technician made all the measurements. In particular, measures included height, weight, eight girth measurements (upper arm flexed and tensed, maximum, minimum, and normal thoracic, waist, hip, thigh, and calf), humerus and femur breadth measurements, and six skinfold thickness measurements (triceps, subscapular, suprailiac, abdominal, thigh, and calf).

Standing height was recorded to the nearest 0.1 cm by an anthropometer. Weight was measured using a calibrated electronic scale. Body mass index (BMI) was calculated as body mass/height², where mass was expressed in kilograms (kg) and height in meters (m). Girth was measured by means of a nonstretch spring-loaded tape. In particular, thoracic girth was taken at the mesosternal level: normal thoracic girth during normal breathing, maximum thoracic girth after maximum inhalation, and minimum thoracic girth after a maximal exhalation. Breadth was measured using a sliding compass. Biepicondylar breadth of the humerus was taken between the medial and lateral epicondyles of the humerus, with shoulder and elbow flexed at 90 degrees. Biepicondylar breadth of the femur was taken between the lateral and medial epicondyles of the femur. In both breadth measurements, the technician applied firm pressure on the crossbars in order to compress the subcutaneous tissue (Carter, 2002).

Skinfold thickness was measured to the nearest 0.5 mm with a calibrated Lange caliper (Beta Technology Inc., Cambridge, MD) on the subjects' left side. Each site was measured twice, within a range of 10%, and the average was recorded. Body density was calculated by means of Durnin and Womersley (1974) equations (as suggested by Espana Romero et al., 2009), using three skinfold measurements: triceps, subscapular, and suprailiac. Body fat percentage was calculated using Siri (1956) equation. Subsequently, fat mass and fat-free mass were calculated from total body mass.

Somatotype components, somatotype attitudinal distance (SAD), and somatotype attitudinal mean (SAM) were calculated by means of Heath and Carter equations (Carter, 2002). SAD represents the distance between an individual somatotype and the mean somatotype for the group or between two somatopoints or two somatotype group means. SAM is the SAD average and measures the scatter of individual somatotypes about the subjects' mean (Carter, 2002).

Values are expressed as mean±standard deviation. Statistical comparisons between mean values from literature were performed by means of Student t-test; significance level was set at p<0.05. The statistical package Statistica for Windows 7.1 was used for all analyses.

Results and Discussion

Descriptive statistics of the subjects' anthropometric characteristics are shown in Table 1. Mean BMI indicates a normal nutritional status. According to WHO cut-off values (James et al., 2001), none had a BMI indicating overweight (BMI≥25 kg/m²) or underweight (BMI<18.5 kg/m²). BMI range was 21.45–24.82 kg/m². Fat mass percentage is 11.76±2.93%.

Table 1 also shows the comparison (mean, SD, and p value of t-test) with a group of 53 Italian male adults (Toselli and Gualdi-Russo, 1999). The subjects in the present study have significantly more fat free mass, less fat mass, lower fat mass percentage, smaller skinfolds, and lower body mass, even if they were significantly older and their height was not significantly different. Both samples are from Northern Italy. Body composition was assessed with different methods (skinfolds vs. bioelectrical impendence). Even if this fact could bias the comparison, to date no other comparable data are available.

The average somatotype is 1.55–5.28–2.64. Mesomorphy is the dominant somatotype component in all but one the subjects of the sample, as in the Italian males who practice sport on a regular basis (Gualdi-Russo and Graziani, 1993). As expected, endomorphism is low. The somatoplot of the mean somatotype and of each subject is shown in Figure 1: eight subjects out of ten (equal to 80% of the examined sample) belong to the ectomorphic mesomorph category, one to the endomorphic mesomorph category, and one to the mesomorphic ectomorph category.

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FIG. 1.

Distribution of climbers' individual () and mean () somatotypes of our study and comparison with mean somatotypes in other climbing activities. FC, free climbing; MC, mountain climbing.

As shown in Table 2, SAM value is 1.05, which indicates that our sample is the most homogeneous, since the homogeneity of the group increases as SAM value decreases (Carter, 2002).

Comparisons were made with athletes involved in other climbing activities, in order to evaluate sport-specific anthropometric characteristics (Table 3). The subjects in the present study are heavier and have a higher fat percentage, on average, even if the height is not significantly different. Exceptions are Egocheaga et al. (1998) mountain climbers, who have a higher body fat percentage, and Mermier et al. (2000) free climbers, who have a higher body weight. Several factors may influence these results: age, ethnicity, sport discipline (e.g., mountain climbing vs. free climbing), nutrition, and training modalities. Also, it must be taken into consideration that the subjects were evaluated a month before the ascent. Since climbers lose weight at high altitude (Boyer and Blume, 1984; Reynolds et al., 1999; Rose et al., 1988), we can presume that the athletes purposefully tried to gain weight prior to departure. In particular, body fat percentages are significantly higher (p<0.01) than in experienced free-climbers (Bertuzzi et al., 2001; Egocheaga et al., 1998; Watts et al., 1993) and world-class boulderers (Michailov et al., 2009), even if different calipers and %BF equations may have influenced the obtained results.

The athletes' low body fat could be related to performance in sports where strength-to-mass ratio is the key (Bertuzzi et al., 2005; Mermier et al., 2000; Watts et al., 1993; Watts et al., 2003), or endurance is dominant, as suggested in Viviani and Calderan (1991).

Compared to other forms of mountaineering though, high altitude mountain climbing requires more physical endurance than free-climbing (or sport rock climbing). In fact, the former involves long distances to be covered at high altitude on foot in adverse environmental conditions and carrying heavy rucksacks. The latter instead consists of shorter efforts and is more strength-oriented.

We can suppose that in mountain climbing, the athlete's body weight is lifted differently than in free-climbing. In the former, the athlete uses mainly the lower body strength (especially leg strength) to complete the ascent. In the latter, the upper body strength (especially grip and arm strength) is more involved. Relative strength is more sensitive to body mass variations when the strength of weaker (i.e., upper body) muscles is involved. Therefore, a higher body mass and fat percentage is more detrimental to performance in free-climbing, since the absolute upper body strength is inferior to the lower body one.

Generically, the mesomorphic somatotype is associated to the fittest individuals (Carter and Heath, 1990). At the same time, Mermier et al. (2000) have suggested that most variables predicting performance in mountain climbing are training-related, such as strength and endurance, and not anthropometric-related, such as height and weight. Still, the present study suggests that mesomorphism could be the dominant somatotype in elite, high altitude mountain climbers. These two findings are not necessarily inconsistent. In fact, some of the anthropometric components that determine the dominant somatotype are conditioned by training, for example, muscle hypertrophy (therefore girths and body weight) and body fat (therefore skinfolds).

Comparisons of average somatotypes with other studies on climbers are shown in Table 4 and in Figure 1. In particular, the present study's subjects are significantly less endomorphic, more mesomorphic, and less ectomorphic than Viviani and Calderan's top-level European free climbers. Moreover, Viviani and Calderan's free climbers are the furthest (SAD=1.72), while Egocheaga et al.'s mountain climbers are the closest to our sample (SAD=1.14). These values support our thesis that mountain climbers have specific anthropometric characteristics, different from those of free climbers.

Low body fat, low endomorphism, and dominant mesomorphism characterize the current sample's subjects. Such anthropometric profile may favor success in mountain climbing. Some limitations to this study should be recognized: the hydration status of the participants was not taken into consideration and the sample size is not large. The availability of a homogeneous sample of elite mountain climbers together with the standardization of anthropometric methodology are notable strengths.

Nonetheless, further research on wider samples is needed in order to confirm these findings. Studies on intermediate or amateur climbers may provide useful information about somatotype and body composition in relation to performance levels.

Since the athlete lifts his/her own body weight against gravity, a low body fat percentage and low endomorphism should be expected when dealing with experienced mountain climbers, as in other sports where strength-to-mass ratio (i.e., relative strength) is positively correlated to performance. It may be relevant to highlight the fact that in other forms of mountaineering, such as free climbing, where relative strength is more crucial than in mountain climbing, body fat is lower, even if in the latter endurance is more relevant than in the former.

At the same time, it must be taken into consideration that anthropometric characteristics are conditioned by sport practice (Watts, 1993). Therefore, training should be directed towards attaining lower body fat percentages and higher relative strength, which are typical of the mesomorphic-dominant athlete.