I.J. Fitness (2009) 5, Issue 1,.pp. 41-49
Aerobic fitness, running performance and body composition of Czech elite male summer biathletes R. Psotta\ D. Sviráková', V. Bunc', I. Seflová', P. Hrásky'and A. J. Martin' 1.2,3.4.5 Qi^g^Qg University Prague, Faculty of Physical Education and Sport, Czech Republic "MasseyUniversity, PalmerstonNorth, NewZealand. E-mail:
[email protected] Abstract. In contrast to distance track running, information on the physiological characteristics of athletes trained In cross-country running (summer) biathlon does not exist. Therefore the aim of the study was to assess the physiological profile of Czech elite male summer biathletes. Male summer biathletes (n=14) aged 22.9(±5.8) years, trained for 6-15 years, were tested using an incremental running test on the treadmill with a 5 % inclination. During the test selected cardiorespiratory and performance variables were assessed. Body fat, body cell mass (BCM) and extracellular mass (ECM) were assessed using the bio-electrical impedance method. Mean VO^max and peak running speed (vmax) were 64.3(±5.2) ml. kg"' min' and 17.4(±1.2) km.h"', respectively. The selected physiological and performance variables at the ventilatory threshold (VT) were as follows: VOj = 53.0 (±5.0) ml. kg' min', % VOjmax at the VT level = 82.6(±2.2%), speed of running = 14.4(±1.0) km.h"', % vmax = 81.5(±7.1 ) % and the energy cost of running C = 3.78 (±0.48) J.kg'.m"'. Both maximal aerobic power and aerobic capacity of the biathletes was 5-10 % lower than those of middle and long distance track runners found in previous studies. The C in biathletes suggested that training with the majority of running on a course with variable slope and a natural surface could affect to a similar degree of mechanical adaptation as training with the majority of running on a flat track. The ECM/BCM ratio= 0.73(±0.08) found in summer biathletes suggested that summer biathlon training can affect changes in body composition which are similar to the adaptation to endurance high intensity exercise found in distance track runners. The data presented in this study can also serve as preliminary physiological standards for the evaluation of the training status in subjects involved in summer biathlon training. Keywords .Biathlon, Oxygen consumption. Economy of running. Body composition.
Introduction Cross-country running biathlon is the most common version of summer biathlon and involves a combination ofprolonged running on a course includingflat,uphill and downhill parts surfaced with grass, sawdust, asphalt or cinder, and small-bore shootingfrom50 m at metallic silhouette targets. This physical activity has been developed as a competitive sport mainly in the last fifteen years in Central Europe, Scandinavia and North America. In addition, cross-country running biathlon has become a popular leisure sport for both adults and the youth. However, in contrast to both winter biathlon and distance running sports, information on the physiological characteristics of summer biathletes does not exist. Knowledge of physiological characteristics of athletes is an important resource for understanding the physiological demands of a given sport, and consequently for planning effective training programmes. In cross-country running biathlon, lower level physiological capacity can not only limit running speed, but also stimulate physical fatigue of a biathlete which can negatively affect postural stability (Pendergrass et al., 2003; Nardone et al, 1997), and as a result, the shooting performance can be disturbed. Decrease in the number of shot hits and shooting accuracy from standing shooting was found in winter biathletes with higher physiological loading (Hof&nan © 2009 Fitness Society of India
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R. Psotta, D. Sviráková, V. Bunc, l. éeflovà, P. HráskyandA. J. Martin
et al., 1992). Maie cross-country running biathlon includes various competitions which differ with course lengths, shooting specification and shooting penalties (Geistlinger et al,, 2006) (Table í), ' " Tabie 1. The characteristics of various competitions of male cross-country running biathlon
Type of competition
ENDURANCE Shooting bouts Course length 30 s
4km 70 m penalty loop RELAY
PURSUIT and MASS START Course length 6 km 70 m penalty loop
Legend; P prone shooting,
Shooting bouts P, P, S, S
Shooting bouts 00 ft.."
.
Type of competition
Shooting penalty
00 ft,." oo" 0."
7km Shooting penalty
SPRINT Course length
Course length 4 x4km
Shooting bouts P,S
3 spare 70 m penalty loop rounds per bout
S standing shooting
The course in the male cross-country running biathlon varies from 4 km in sprint competition to 7 km in endurance competition (Table 1). Thus, the total distance covered during a running biathlon race is similar to middle or long distance in running races on a track. The maximal oxygen uptake (V02max) of track runners and cross-country runners was identified as the deciding factor of their running performance on distances from 2 to 16 km (Bassett and Howley, 2000; Fay et al., 1989). Middle and long distance running performance strongly depends also on thefractionalutilization of VO^max (Brandon, 1995; Bunc and Heller, 1994), i.e. on the ability to utilize effectively functional capacity during prolonged exercise. During middle distance race performance, the relative contribution of the aerobic energy system was found to be 80-84 % in trained track runners of both genders (Spencer and Gastin, 2001; Hill, 1999). These fmdings suggested that the rest of the energy needed for muscle contractions and functioning of the cardiopulmonary system is probably produced from anaerobic glycolysis. In previous studies anaerobic capacity was found as one of the important determinants for both middle distance running performance (Brandon and Boileau, 1992) and long distance running performance (Houmard et al., 1991; Bulbulian et al., 1986) in track and cross-country runners. Besides the physiological adaptations, biomechanical adaptations are decisive for miming performance, i.e. running economy is an important determinant of middle and long distance running performance (Brandon, 1995; diPrampero, 1986). In comparison to middle and long distance running on the track, the physiological demands of cross-country nirming biathlon could be different due to the specificity of neuromuscular coordination while running on crosscountry terrain and the repeated interruption of running by two or four shooting series at the shooting-range (Table 1 ). Therefore the aim of this study was to assess physiological profile of elite Czech male summer biathletes. Material and Methods Participants: Fourteen Czech elite male summer biathletes volunteered to participate in the
Aerobic Fitness, Running Performance and Body Composition of Biathletes
43
study that was approved by the Faculty of Physical Education and Sports Ethics committee, Charles University, Prague. Their age, body height and body mass are shown in Table 2. All biathletes were specialists in cross-country running biathlon and participated in summer biathlon races at the Czech national level. They had been training for cross-country running biathlon for 6-15 years. In the last year, their training program had involved usually five to eight training sessions a week of 60 to 120 minutes of duration per session, plus thirteen summer biathlon races on average. Approximately one third of their training sessions were specifically focused on shooting at rest and combined running and shooting. Two thirds of the sessions concentrated on improvement of aerobic and anaerobic endurance and running speed using running exercises on both terrain and track, supplemented with strength training. Table 2. Age and basic anthropométrie characteristics of the male summer biathletes (mean ±SD).
Age (years)
Body height (cm)
22.9 ±5.8
179.3 ±8.3
Total body mass (kg) 69.0 ± 10.1
Anthropométrie Measurements: Measurements of the body height and the total body mass were made according to the standard anthropométrie techniques recommended by MacDougall and Wenger (1991). All measurements were carried out by the same person using the same equipment. Standing height was measured without shoes to the nearest 0.5 cm, using a wall stadiometer (model 220, Seca, Hamburg, Germany). Total body mass was measured to the nearest 0.1 kg, using an electronic scale (model TH 0641, Soehnle, Nassau, Germany) with the subjects wearing only training shorts. The scale was calibrated before and after each testing session. Body Composition Assessment: The measurement of body height, total body mass and body composition were performed at the beginning of each testing session. The body composition was assessed by the bio electrical impedance method using the multi frequency analyser (B.I. A. 2000M, Data Input, Germany). This method consisted of the measurement of the resistance and reactance at 1,5,50 and 100 kHz frequencies on the right side of the body of the subject by tetra polar electrode configuration, with two electrodes on the hands and two on the feet in accordance with the recommendations of the manufacturer (Segal et al., 1991). Electrodes on the hands were placed dorsally in the web space between metacarpals II and III for the signal electrode and dorsally on the wrist between the radius and the ulna for the measuring electrode. Electrodes on the feet were placed dorsally in the web space between metatarsals I and II for the signal electrode and anterior laterally at the ankle between the tibia and fibula for the measuring electrode. The body fat percentage was determined by the prediction equations verified by the DEXA method (Bunc, 2001 ). Fatfreemass (FFM) was calculatedfromthe classical two-compartment model of body composition body mass = body fat+fat-free mass (BM=BF+FFM). In addition, the molecular model of the body composition fat-free mass = extracellular mass + body cell mass (FFM=ECM+BCM) (Roche et al., 1996) was also used. The BCM was assessed by means of the bio-electrical impedance rrieasurément method and calculated as BCM = FFM multiplied by the phase angle between the whole impedance vector and resistance and
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R. Psotta, D. Svlrakovà, V. Bunc, I. Seflovà, P. HráskyandA. J. Martin
multiplied by the constants (Kushner and Schoeller, 1986). The extracellular mass (ECM) was calculated as the difference between FFM and BCM. The ratio ECM/BCM was calculated for evaluation of the subject's adaptation of the body composition at the molecular level due to physical training. The subjects were tested in the laboratory during the two final weeks of their competitive season (October). A rest day preceded the day of the laboratory testing session. Assessment of Physiological and Performance Characteristics: To determine their physiological profile, the subjects were tested using an incremental exercise protocol on the treadmill with 5 % inclination (Bunc, 1989). Warming-up of the subjects was performed on a treadmill with 0 % inclination for 4 min at speed 11.0 and 13.0 km.h"'. The initial testing speed 13.0 km.h"' was increased every minute by 1.0 km.h"' until voluntary exhaustion. The cardiorespiratory variables were assessed using an open system with the help of TEEM 100 equipment (AeroSport, Ann Arbor, Mich.) (Novitsky et al., 1995). The cardiorespiratory variables were calculated automatically every 20 seconds. The mean of three consecutive observations was calculated for the final results. The ventilatory threshold (VT) was assessed by means of the two-compartment linear model from the relation of pulmonary ventilation to oxygen uptake or CO^ output. This was done by computer algorithm in order to establish a twoline regression intersection point (Bunc et al, 1987). The data at VT level were determined by linear interpolation. Economy of Running Assessment: To assess the economy ofrunning, the energy cost of running C was calculated as the amount of energy needed to transport one kilogram of body weight a distance ofone meter expressed in the unit J.kg"'.m"' (Astrand and Rodahl, 1986; DiPrampero et al, 1986). C was calculated from the running speed and oxygen uptake at VT level (VOjVT). The running velocity at VT level was convertedfromthe value determined at the treadmill inclination of 5 % to 0 % using the prediction equations of Bunc (1989). The transformed values of speed and energy consumption determined by using the energy equivalent of oxygen at VT 20.9 J.ml"' (Astrand and Rodahl, 1986;DiPramperoetal, 1986) were usedforthecalculadonofC.
Results The indicators of body composition are presented in Figure 1. The total body mass (TBM) of the male summer biathletes 69.0±l 0.1 kg was composed of 9.6±2.1 % of body fat and 90.4±2.1 % of fat-free mass (FFM). Mean value of FFM of these subjects 62.3±8.5 kg was composed of 58 % of body cell mass (BCM) and 42 % of extracellular mass (ECM). extracellular mass ECM 26.1± 3.1kg 38.0 ± 2.7% of TBM
body fat 6.7± 2.2 kg 9.6 ± 2.1% of TBM
ECM/BCM = 0.7±0.08 FEM = 62.3± 8.5 kg
body cell mass BCM 36.2 ± 5.8 kg 52.4 ± 2.3% of TBM
Figure 1. Absolute and relative body composition measures related to total body mass (TBM; %) Maximal oxygen uptake (VOjmax) and maximal running speed (vmax) was 64.3±5.2 m l kg"'
Aerobic Fitness, Running Performance and Body Composition ofBiathietes
45
min' and 17.4±1.2 km.h', respectively. The selected physiological and performance variables at the ventilatory threshold (VT) were as follows: VOj = 53±5.0 ml. kg"' min', % VO^max at the VT level = 82.6±2.2 %, speed of running = 14.4±1.0 km.h"', % vmax =81.5±7.1 % and the energy cost of running C = 3.78±0.48J.kg"'.m"' (Tables 3 and 4). Table 3. Selected maximal cardio-respiratory measures of male summer biathletes (mean ± SD) VO^max. kg"' (ml.kg'.min"')
Vmax (l.min"')
HRmax (beats.min"')
vmax (km.h"')
64.3 ±5.2
121.6±14.9
195±7
17.4±1.2
Legend: VO^max .kg"' maximal oxygen uptake per one kilogram of body mass, Vmax maximal pulmonary ventilation, HRmax maximal heart rate, vmax maximal speed at the 5 % inclination.
Table 4. Selected cardiorespiratory and performance variables at the ventilatory threshold of male summer biathletes (mean ± SD) %Vo2max (%)
HRVT (beats.min"')
% HRmax (%)
vVT (km.h"')
%vmax
(ml.kg"'.min"')
(%)
C (J.kg'.m"')
53.1 ±5.0
82.6±2.2
176±6
90.3 ±1.5
14.4 ±1.0
81.5±7.1
3.78 ±0.48
Legend: VO2VT oxygen uptake, HRVT heart rate, vVP running speed at 5 % inclination, C energy cost of running
Discussion Body Composition: The percentage of body fat ofthe summer biathletes 9.6±2.1 % suggested a high degree of physical adaptation to aerobic high intensity exercise. Other athletes performing long-term running such as soccer players achieve 8-12 % of body fat (Psotta, 2003,2006) and long-distance track runners 6-8 % of body fat (Crouter et al, 2001 ; Bunc and Heller, 1996). The extra cellular mass and body cell mass ratio ECM/BCM = 0.73±0.08 found in the summer biathletes was very close to values ofthe ECM/BCM ratio reported in very well trained subjects in endurance sports (Bunc et al., 2005). The body cell mass is the sum of glucose oxidising, calcium and protein rich cells and involve the cells in the pure skeletal muscles, heart muscles, inner organs, bones, blood, nodes and the nervous system (Roche et al., 1996). These body systems are responsible for muscle work and indirectly characterize human ability to produce mechanical work. The lower ratio between extra cellular mass and body cell mass (ECM/BCM) is a better predisposition for muscle work (Bunc, 2000). The results of this current study suggest that long-term summer biathlon training can affect the changes in body composition which are typical for adaptation to high intensity endurance exercise. Physiological Characteristics: Mean values of both maximal oxygen uptake (VOjmax) and oxygen uptake at the ventilatory threshold level (VOjVT) related to one kilogram of body mass found in the male summer biathletes (Table 3 and 4) are by 2-12 % lower in comparison to the values of these physiological variables in highly trained middle-distance, long-distance, and cross-country runners found in previous studies (Thomas et al., 2005, DeMaere and Ruby, 1997; Kranenburg and Smith, 1996). In these studies, values of VO^max and VO^VT of well trained distance track runners varied from 66 to 72 ml.kg"'.min"' and from 55 to 60 ml.kg'.
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R. Psotta, D. Sviráková, V. Bunc, I. éeflovà, P. Hràsky and A. J. Martin
respectively. V02max percentage at the VT level serves as an indicator of the subject's ability to utilize effectively the functional capacity during prolonged exercise (Astrand and Rodahl, 1986). The mean value of % VO^max 82.6±2.2 % found in male summer biathletes was similar to the values found in elite adult soccer players (Psotta et al, 2000; Psotta, 2003). However, distance track runners typically manifest highly developedfractionalutilization of Vojmax in the range of 84-90 % (Bunc and Heller, 1996; Cunningham et al. 1990a,b). The results discussed above suggest that both maximal aerobic power indicated by VOjmax .kg', and absolute and relative aerobic capacity indicated by VOjVT.kg"' and % VOjmax, respectively, in elite male summer biathletes are similar to the level of these functional characteristics found in elite middle and long distance track runners. So, demands of the cross-country running biathlon on maximal aerobic power and aerobic capacity seem high. Maximal aerobic power has been shown to be a stronger determinant of performance during uphill running in comparison to flat running (Paavolainen et al., 2000). The relatively lower maximal aerobic power and aerobic capacity of the summer biathletes in comparison to middle and long distance track runners could be partly explained by the fact that the summer biathletes have undergone a combination of running and shooting training with shooting exercises incorporated into one third of all training units in subjects participated in this study. The relatively lower training status of summer biathletes in comparison to elite distance track runners is also supported by their maximal ventilation Vmax values of Vmax being 16-19 % lower than the values of Vmax of middle and long distance track runners measured by the same method by Bunc (1989). The mean value of maximal heart rate HRmax found in the summer biathletes at thefinalpart of the incremental exercise on the treadmill was 195±7 beats.min"'. With the exception of one biathlete, the individual value of HRmax of all subjects measured was higher in comparison to their individual values of HRmax estimated from age using the equation by Inbar et al. (1994). This equation has been accepted as the most accurate for estimation of individual maximal heart rate HRmax (Robergs and Landwehr, 2002). The mean value of measured HRmax was higher by 5 beats, min"' than the mean value of the estimated HRmax (190±4 beats.min'). So, the values of HRmax measured suggested maximal exhaustion of the subjects during the incremental test on the treadmill, and in consequence good validity of the maximal physiological and performance variables found in the study. Rxuining performance characteristics and running economy: Maximal running speed (vmax) is used as the indicator of running speed ability under a maximal rate of oxidative energy production. Then the running speed at the ventilatory threshold (vVT) is usually used as the indicator of the subject's running speed ability under metabolic steady state. The vmax and vVT are determined by both the metabolic capacity to produce the high amount of energy and the ability to use this energy during muscle contractions effectively, i.e. to transfer energy into mechanical power and as a consequence, into horizontal speed of running. Previous studies found vmax and vVT as valid indicators of both cross-country and distance track running performance (Lacour and Candau, 1990, Cunningham, 1990b). The vmax 17.4± 1.2 km.h"' found in the male summer biathletes was approximately 8-9 % lower in comparison to male long distance track runners of similar age measured with the same incremental exercise protocol on the treadmill (Bunc, 1989; Bunc and Heller, 1996). The mean
Aerobic Fitness, Running Performance and Body Composition of Biathletes
47
value of the vVT 14.4 ±1.0 km.h"' found in male summer biathletes was 16 % lower than the mean values of the vVT found in male distance track runners in the study using the same method (Bunc and Heller, 1996). Thus, it is possible to observe the relatively larger differences at vVT than at vmax when comparing the male summer biathletes to male distance track runners. Thesefindingscould suggest relatively better mechanical adaptation of male summer biathletes to running at higher speeds rather than to long distance running under submaximal exercise intensity. The summer biathletes showed very positive economy of running when the coefficient C=3.78±0.48 J.kg"' .m"' was found. These values of the C are only 1 -5 % higher in comparison to the C values measured in highly trained middle and long distance track runners tested using the same method (Bunc and Heller, 1996; Bunc, 1989); The relatively lower running speed at VT level (vVT) of the summer biathletes in comparison to well trained track runners (see above) could be caused by both the lower physiological and oxidative metabolic predispositions and worse running economy. However, on the basis of the relative comparison of the selected physiological variables between the summer biathletes and distance track runners assessed with the same or similar methods, it seems that lower running perfonnance of the summer biathletes is caused by physiological factors rather than economy of running. The slightly lower running economy of summer biathletes in comparison to track runners can be caused by a specific adaptation to the biomechanics of running over cross-country terrain. The study by Jensen et al, (1999) suggested a specific neuromuscular adaptation of running in cross-country terrain, when the running economy on steep terrain was 19 % better in summer biathletes than in track runners although track runners had a 2 % better running economy on aflatpath. Conclusion Both characteristics of aerobic performance maximal aerobic power and aerobic capacity including thefractionalutilization of VOjmax of summer biathletes were only 5-10 % lower in comparison to long and middle distance track runners undergoing typical endurance training. The lower values of the energy cost of running found in the summer biathletes suggested, that long-term summer biathlon training involving typically running on a course with variable slope could affect the mechanical adaptation to a similar degree as distance track running training. Although it is possible to emphasize the aerobic high intensity training of summer biathletes to enhance their aerobic running performance, the training preparation of summer biathletes should, be a balanced combination of running and shooting training. Thefindingsof this current study suggest that preliminary physiological characteristics of adult male cross-country running biathletes should be as follows: VOjmax.kg"' higher than 65 ml. kg'.min"'; % VOjmax at 'anaerobic threshold' higher than 82.5 %; maximal speed of running and the running speed at 'anaerobic threshold' on the treadmill with 5 % inclination higher than 17.5 km.h"' and 14.5 km.h"', respectively; and the energy cost of running lower than 3.80 J. Kg"'.m"'. Demands of cross-country running biathlon on the body corhposition of adult male biathletes are as follows: body fat under 10 % of total body mass and the ECM/BCM ratio lower than 0.75. References Astrand, P,0, and Rodahl ; K, ( 1986) Textbook ofworkphysiology. 3rd edition. New York: McGraw-Hill,
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R. Psotta, D. Sviráková, V. Bunc, I. èeflovà, P. HràskyandA. J. Martin
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Acknowledgments The study was supported by the grant from Ministry of Education, Youth and Physical Education of Czech Republic MSM 0021620864
