Prof. GrĂŠgoire Millet Very short supra-maximal Interval-Training allows circumpubertal boys t maintain to i t i VO2max for f greater t duration d ti than th adults d lt
VO2 kinetics Model
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1
VO2 kinetics Model
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Murgatroyd SR, Ferguson C, Ward SA, Whipp BJ, Rossiter HB (2011) Pulmonary O2 uptake kinetics as a determinant of high-intensity exercise tolerance in humans. Journal of Applied Physiology 110: 1598-1606
VO2 kinetics Model
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CP is generally agreed to represent a threshold of aerobic function and corresponds to the highest work rate for which steady states in pulmonary O2 uptake, arterial blood acid-base status (lactate, bicarbonate and hydrogen ions) and intramuscular phosphate (phosphocreatine and inorganic phosphate) responses can be achieved … demarcates the upper limit of ‘wholly aerobic’ energy provision W′ is the curvature constant of the hyperbola Mathematically equivalent to a constant amount of work that can be performed above CP, i.e. the product of supra-CP Power and tlim Murgatroyd SR, Ferguson C, Ward SA, Whipp BJ, Rossiter HB (2011) Pulmonary O2 uptake kinetics as a determinant of high-intensity exercise tolerance in humans. Journal of Applied Physiology 110: 1598-1606
2
VO2 kinetics Model
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Murgatroyd SR, Ferguson C, Ward SA, Whipp BJ, Rossiter HB (2011) Pulmonary O2 uptake kinetics as a determinant of high-intensity exercise tolerance in humans. Journal of Applied Physiology 110: 1598-1606
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Effects of training 1. Speed the kinetics ( 1) 2. Reduce amplitude of the slow component ( VO2sc) 3. Improve the economy
Time (s)
3
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1 = time constant (s) of the primary phase
* *
*
1 = 8 – 10 s
Jones, A.M. The physiology of the World record holder for the Women’s marathon. International Journal of Sports Science & Coaching 1:101-115, 2006.
1 = time constant (s) of the primary phase Maturation effect
35
*
30
*
25
*
20
15
10
5
0 12y
13y
14y
15y
4
1 = time constant (s) of the primary phase Maturation effect
11 yr y old
*
*
13 yr old
Slows the kinetics ( 1) Increases amplitude of the slow component ( VO2sc)
Fawkner SG, Armstrong N (2004) Longitudinal changes in the kinetic response to heavy‐intensity exercise in children. Journal of Applied Physiology 97: 460‐466
Applications : Interval-training A
B
95% VO2 SS (A)
50% VO2 SS (B) interval = 30 s
5
30s~30s100%
80 70
100
60
90
50 40 30 20
VO2max
10
80 70 60
0
50
80 70
40
VO2 (ml/kg/min)
60
30
50 40 30
Tlim li
20
20 10 0
10 0
100
100
90
90
80
80
70
70
60
60 50
50
40
40
30
30 20
20
10
10
0
0
½Tlim~ ½Tlim 100%
60s~ 30s100%
Millet GP, Candau R, Fattori P, Bignet F, Varray A (2003) VO2 responses to different intermittent runs at velocity associated with VO2max. Canadian Journal of Applied Physiology 28: 410‐423
Test
VO2 pic (ml.kg-1.min-1)
FC (b.min-1)
VAM-eval VAM eval
71 1 ± 3.9 71.1 39
aa
192 8 ± 10.1 192.8 10 1
Tlim
69.5 ± 4.2
a
186.9 ± 9.2*
30 s ~ 30 s
65.4 ±±4.9 65.4 4.9
183.1 ± 8.5*
60 s ~ 30 s
71.7 ± 4.8
aa
188.8 ± 10.4*
½Tlim~½Tlim
72.2 ± 6.1
aaa
187.0 ± 11.4*
a = P < 0.05, aa = P < 0.01, aaa = P < 0.001 : différences avec 30s~30s * = P < 0.001: différences avec test VAM-éval
Millet GP, Candau R, Fattori P, Bignet F, Varray A (2003) VO2 responses to different intermittent runs at velocity associated with VO2max. Canadian Journal of Applied Physiology 28: 410‐423
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Temps (s) passé : Intermittent
> 90% FC max
> 90% VO2 max
30 s ~ 30 s
148.6 ± 132.8
441.0 ± 317.4
60 s ~ 30 s
530.8 ± 187.1
aaa
744.5 ± 207.2
aa
½Tlim~½Tlim
486.3 ± 176.2
aaa
632.6 ± 153.8
a
a = P < 0.05, aa = P < 0.01, aaa = P < 0.001 : différences avec 30s~30s
Millet GP, Candau R, Fattori P, Bignet F, Varray A (2003) VO2 responses to different intermittent runs at velocity associated with VO2max. Canadian Journal of Applied Physiology 28: 410‐423
100% vVO2max 80 70 60 50 40
450
r = 0.91; P < 0.01
30
400 20
350
C
Time ≥ 90% VO2max (s) (∆ IT 105% - IT 100%)
10 0
80 80 70
300 250 200 150
60
100
50
50
40
0 0
30 20 10 0
5
10
15
20
25
1
D
105% vVO2max
Millet GP, Libicz S, Borrani F, Fattori P, Bignet F, Candau R (2003) Effects of increased intensity of intermittent training in runners with differing VO2 kinetics. European Journal of Applied Physiology and Occupational Physiology 90: 50‐57
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• VO2 kinetics is paramount for describing/ developing (?) aerobic fitness and endurance performance. Fast VO2 kinetics allows the use of shorter work kinetics allows the use of shorter work‐interval interval • Fast VO • Children have faster VO2 kinetics than adults • Would children benefit more than adults of using very short work‐intervals in order to sustain long time near/at VO2max ?
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Boys (n = 8)
Men (n = 8)
Age (yr)
14.3 ± 0.9
30.1 ± 7.6 ***
Height (cm)
162.9 ± 7.8
174 ± 5.8 **
Weight (kg)
50.6 ± 9.0
69.4 ± 10.0 ***
• 200‐m indoor synthetic running track over a 3‐week period. y g p • A maximal incremental test to exhaustion ‐> VO2max and vVO2max. vVO2max (km.h) HRmax (bpm) VO2max (ml.kg.min)
15.6 ± 2.3
17.2 ± 1.3 **
206 ± 8
190 ± 8 **
62.2 ± 8.5
60.5 ± 5.9
• 2 bouts of 6 min at a velocity associated with their ventilatory threshold ‐> VO2 kinetics. 1 (s)
19.0 ± 3.6
26.3 ± 6.7 s *
• 3 supramaximal intermittent running sessions, at velocities representing 110% (work interval) and 50% of vVO2max (recovery 16 interval).
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##
350
300
* 250
200
Boys Men
150
100
50
0 10s~10s
20s~20s
30s~30s
Time (s) > 95% VO2max
250
## 200
150
100
Boys Men
*
**
50
0 10s~10s
20s~20s
30s~30s
Time (s) at VO2max
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• Longer time near/at VO2max in 10s~10s than in 30s~30s in boys • No difference between 10s~10s , 20s~20s and 30s~30s in adults. • Circumpubertal Circumpubertal boys spent 5x longer time at VO boys spent 5x longer time at VO2max than adults than adults with short work‐interval duration (10s or 20s) whereas there was no differences with 30s. • Since the kinetics in adolescents is faster, they benefit more from shorter work‐interval than adults
• Might help better adjusting IT sessions throughout the teenage period where two contradictory mechanisms happen: Maturation ‐> slows the kinetics Increase in aerobic fitness ‐> speeds the kinetics. 19
Thank you
Any Questions ?
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Few steps beyond.. La préparation physique. D. Legallais & G. Millet
2007, Masson
L’endurance. Millet G. (ed), 2006
S’entraîner en altitude G. Millet & L. Schmitt
2011, deBoeck Univ
Edition EPS
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