S82
Anaerobic Performance at Altitude J. Coudert Laboratory of Physiology and Sports Biology, Faculty of Medicine, BP 38-6300 1 Clermont-Ferrand, France
J. Coudert, Anaerobic Performance at Altitude.IntJSportsMed,Vol 13,Suppl 1,ppS82—S85, 1992.
The observations made during sports events at altitude are also an area which can be used to investigate anaerobic performances. Records at the Mexican Olympic Games (1968)
Anaerobic metabolism is usually evaluated by the determination of the anaerobic capacity and the maximal anaerobic mechanical external power (Wmax).
Although Mexico is located at a moderate altitude (2270 m, barometric pressure [PB] 560 Torr), the records for the various athletic sports events highlighted that
Conflicting results are reported on anaerobic capacity eval-
long distance running performances (over 800 m) which principally have recourse to aerobic metabolism, were re-
uated by maximal oxygen deficit and debt, and maximal blood lactate concentration during acute or chronic hypoxia (acclimatized subjects). Data on muscle biopsies (lactate concentration, changes in ATP, phosphocreatine and glycogen stores, glycolytic enzyme activities) and the few studies on lactate flux give in most cases evidence of a non-alteration of the anaerobic capacity for altitudes up to 5,500 m. No differences are observed in Wm measured at high altitudes up to 5,200 m during intense short-term exercises: (1) jumps on a force platform which is a good indicator of alactic Wmax, and (2) 7—lOs sprints (i.e. force-velocity
test) which sollicit alactic metabolism but also lactic pathway. For exercises of duration equal or more than 30 s (i.e. Wingate test), there are conflicting results because a lower participation of aerobic metabolism during this test at high altitude can interfere with anaerobic performance.
In conclusion, we can admit that anaerobic performances are not altered by high altitudes up to 5,200 m if the length of exposure does not exceed 5 weeks. After this period, muscle mass begins to decrease.
duced and that short distance performances, where anaerobic metabolism plays a major role, were improved. The improvement in records over short distances is of course linked, to a large extent, to the reduction in air density (a 24% drop in Mex-
ico). However, using the hyperbolic model of Péronnet et a!. (29) to predict world records at altitude, it is possible to note that the improvement observed in Mexico for the 400 m (1.6% higher than the record at sea level) is greater than the prediction (+ 1.36%). With this model, anaerobic capacity is estimated to be the same as at sea level. If this model is valid, it can be said that the anaerobic capacity of athletes, acclimatized to Mexico's altitude, is not altered.
Evaluation of Anaerobic Capacity
(Tables 1,2 and 3) Looking at the overall results, the following remarks can be made:
1. Data, which were most often different, were collected in varying experimental situations: — after exercises varying in
Key words
Hypoxia, anaerobic capacity, maximal anaerobic power, acclimatization
Introduction
The effect of altitude on anaerobic performances still remains a subject for discussion and gives rise to conflicting results. The methods used to evaluate this effect can be grouped under two headings: 1) evaluation of anaerobic capacity by measuring principally maximal 02 deficit and debt (DO2max) and determination of maximal blood lactate concentrations ([L ]bmax) after maximal or supramaximal exercises; 2) measurement of external mechanical power after intense short-term exercises. Int.J.SportsMed. 13(l992)S82—S85 Georg Thieme Verlag Stuttgart New York
intensity and duration (submaximal, maximal and supramaximal), from subjects with different training levels, either highland or lowland natives and subject to different acclimatization periods in environmental conditions which are difficult to compare. In fact, can we compare a group of mountainers, during expeditions, subject to the combined stress of the extreme altitude, cold and sport activity to a group of subjects observed in a hypobaric chamber, even if the simulated altitudes are similar?
2. It is generally known that there is a high correlation between blood [L }b and muscle ([L ]m) lactate (21) at sea level,
even after maximal short-term exercises (30 s sprint) (8). The situation appears to be different in acute and chronic hypoxia, where there exists a clear dissociation between [L ]b and [L ]m. Moreover, it is only from the altitude of 5,500 m (PB = 380 Torr) that [Urn are lower than those observed at sea level (15).
Downloaded by: Queen's University. Copyrighted material.
Absfract
mt. J. Sports Med. 13(1992) S83
Anaerobic Performance at Altitude Table 1 Variations in maximal 02 deficit and debt (DO2max) in acute (AN) and chronic (CH) hypoxia, and normoxia (N). Wex
Changes
References
max) in acute (AN) and chronic (CN) hypoxia, and normoxia (N).
Altitude
Wex
AN vs N
3400 m (HC) 4100 m (I-IC)
maximal 114% VO2max
4400 m (F102=0.12)
maximal
=
/ .'
(25) DO2max (23) MaxO2 deficit + DO2max (1) DO2max
CHvsN 2270 m 2300 m 3700 m
3700m
Maximal Supramaximaf 90%VO2max 115%VO2max
= =
\ =
(30) DO2max (9) DO2max (31) DO2max (12) DO2max (children 10—12 years, HL vs LL)
Wex: exercise power; NC: hypobaric chamber; NL vs LL: Highlanders vs Lowlanders
Comparisons indicate; =: unchanged;f: increased;: decreased.
observations highlight the danger of realizing an extrapolation from [L}b max to evaluate anaerobic capacity at real and simulated altitudes. These
3. Most studies give a drop in [L]b max among acclimatized subjects. To explain this phenomenon the following propositions have been made:
a. The drop in muscle and blood buffer capacity: after acclimatization at 5,350 m, Cerretelli et al. (7) observed
that the fall in blood bicarbonate concentration ([HCO31) induced a considerable fall in blood and muscle buffer capacities. The decrease in pH would im-
pair in particular the phosphofructo-kinase activities and consequently would limit the possibility of muscle lactate production. At 3,700 m, Le François et al. (24) found no decrease but
increase in blood buffer capacity among acclimatized
subjects. At this altitude, the effects of the drop in [HCO37 would be compensated by the increase in
3400 m (HC) 3800 m (F102 4300 m (HC) 4400 m (F102 4100 m (HC) 4300 m 4400 m (Fl02 4270 m (NC) 4400 m (F102 4800 m (Fl02
b. The more rapid disappearence of blood lactate has been observed at altitude by certain authors: at 3,700 m, we
observed among acclimatized subjects a more rapid decrease in [L]b in children born and living in La Paz (tt/ 2 disappearance: 8.8 2.8 mm at HA, 14.4 5.5 at low altitude, p
Anaerobic Performance at Altitude J. Coudert Laboratory of Physiology and Sports Biology, Faculty of Medicine, BP 38-6300 1 Clermont-Ferrand, France
J. Coudert, Anaerobic Performance at Altitude.IntJSportsMed,Vol 13,Suppl 1,ppS82—S85, 1992.
The observations made during sports events at altitude are also an area which can be used to investigate anaerobic performances. Records at the Mexican Olympic Games (1968)
Anaerobic metabolism is usually evaluated by the determination of the anaerobic capacity and the maximal anaerobic mechanical external power (Wmax).
Although Mexico is located at a moderate altitude (2270 m, barometric pressure [PB] 560 Torr), the records for the various athletic sports events highlighted that
Conflicting results are reported on anaerobic capacity eval-
long distance running performances (over 800 m) which principally have recourse to aerobic metabolism, were re-
uated by maximal oxygen deficit and debt, and maximal blood lactate concentration during acute or chronic hypoxia (acclimatized subjects). Data on muscle biopsies (lactate concentration, changes in ATP, phosphocreatine and glycogen stores, glycolytic enzyme activities) and the few studies on lactate flux give in most cases evidence of a non-alteration of the anaerobic capacity for altitudes up to 5,500 m. No differences are observed in Wm measured at high altitudes up to 5,200 m during intense short-term exercises: (1) jumps on a force platform which is a good indicator of alactic Wmax, and (2) 7—lOs sprints (i.e. force-velocity
test) which sollicit alactic metabolism but also lactic pathway. For exercises of duration equal or more than 30 s (i.e. Wingate test), there are conflicting results because a lower participation of aerobic metabolism during this test at high altitude can interfere with anaerobic performance.
In conclusion, we can admit that anaerobic performances are not altered by high altitudes up to 5,200 m if the length of exposure does not exceed 5 weeks. After this period, muscle mass begins to decrease.
duced and that short distance performances, where anaerobic metabolism plays a major role, were improved. The improvement in records over short distances is of course linked, to a large extent, to the reduction in air density (a 24% drop in Mex-
ico). However, using the hyperbolic model of Péronnet et a!. (29) to predict world records at altitude, it is possible to note that the improvement observed in Mexico for the 400 m (1.6% higher than the record at sea level) is greater than the prediction (+ 1.36%). With this model, anaerobic capacity is estimated to be the same as at sea level. If this model is valid, it can be said that the anaerobic capacity of athletes, acclimatized to Mexico's altitude, is not altered.
Evaluation of Anaerobic Capacity
(Tables 1,2 and 3) Looking at the overall results, the following remarks can be made:
1. Data, which were most often different, were collected in varying experimental situations: — after exercises varying in
Key words
Hypoxia, anaerobic capacity, maximal anaerobic power, acclimatization
Introduction
The effect of altitude on anaerobic performances still remains a subject for discussion and gives rise to conflicting results. The methods used to evaluate this effect can be grouped under two headings: 1) evaluation of anaerobic capacity by measuring principally maximal 02 deficit and debt (DO2max) and determination of maximal blood lactate concentrations ([L ]bmax) after maximal or supramaximal exercises; 2) measurement of external mechanical power after intense short-term exercises. Int.J.SportsMed. 13(l992)S82—S85 Georg Thieme Verlag Stuttgart New York
intensity and duration (submaximal, maximal and supramaximal), from subjects with different training levels, either highland or lowland natives and subject to different acclimatization periods in environmental conditions which are difficult to compare. In fact, can we compare a group of mountainers, during expeditions, subject to the combined stress of the extreme altitude, cold and sport activity to a group of subjects observed in a hypobaric chamber, even if the simulated altitudes are similar?
2. It is generally known that there is a high correlation between blood [L }b and muscle ([L ]m) lactate (21) at sea level,
even after maximal short-term exercises (30 s sprint) (8). The situation appears to be different in acute and chronic hypoxia, where there exists a clear dissociation between [L ]b and [L ]m. Moreover, it is only from the altitude of 5,500 m (PB = 380 Torr) that [Urn are lower than those observed at sea level (15).
Downloaded by: Queen's University. Copyrighted material.
Absfract
mt. J. Sports Med. 13(1992) S83
Anaerobic Performance at Altitude Table 1 Variations in maximal 02 deficit and debt (DO2max) in acute (AN) and chronic (CH) hypoxia, and normoxia (N). Wex
Changes
References
max) in acute (AN) and chronic (CN) hypoxia, and normoxia (N).
Altitude
Wex
AN vs N
3400 m (HC) 4100 m (I-IC)
maximal 114% VO2max
4400 m (F102=0.12)
maximal
=
/ .'
(25) DO2max (23) MaxO2 deficit + DO2max (1) DO2max
CHvsN 2270 m 2300 m 3700 m
3700m
Maximal Supramaximaf 90%VO2max 115%VO2max
= =
\ =
(30) DO2max (9) DO2max (31) DO2max (12) DO2max (children 10—12 years, HL vs LL)
Wex: exercise power; NC: hypobaric chamber; NL vs LL: Highlanders vs Lowlanders
Comparisons indicate; =: unchanged;f: increased;: decreased.
observations highlight the danger of realizing an extrapolation from [L}b max to evaluate anaerobic capacity at real and simulated altitudes. These
3. Most studies give a drop in [L]b max among acclimatized subjects. To explain this phenomenon the following propositions have been made:
a. The drop in muscle and blood buffer capacity: after acclimatization at 5,350 m, Cerretelli et al. (7) observed
that the fall in blood bicarbonate concentration ([HCO31) induced a considerable fall in blood and muscle buffer capacities. The decrease in pH would im-
pair in particular the phosphofructo-kinase activities and consequently would limit the possibility of muscle lactate production. At 3,700 m, Le François et al. (24) found no decrease but
increase in blood buffer capacity among acclimatized
subjects. At this altitude, the effects of the drop in [HCO37 would be compensated by the increase in
3400 m (HC) 3800 m (F102 4300 m (HC) 4400 m (F102 4100 m (HC) 4300 m 4400 m (Fl02 4270 m (NC) 4400 m (F102 4800 m (Fl02
b. The more rapid disappearence of blood lactate has been observed at altitude by certain authors: at 3,700 m, we
observed among acclimatized subjects a more rapid decrease in [L]b in children born and living in La Paz (tt/ 2 disappearance: 8.8 2.8 mm at HA, 14.4 5.5 at low altitude, p
