NUTRITION IN SPORT

was used during the first 5–6 s of the race. The
decrease in running speed over the 100 m com-
menced when the high-energy phosphate stores
were markedly reduced and glycolysis was the
predominant energy provider. Lactate did not

536 sport-specific nutrition

accumulate to a level which could have inhibited

glycolysis and is unlikely to have been the princi-

pal cause of fatigue. These results show that the

rate of PCr utilization is critical to running speed.

In agreement with these results, Locatelli and

Arsac (1995) showed that anaerobic glycolysis

provided approximately 65–70% of the meta-

bolic energy production during a 100-m race in

their study of four male and four female national

sprinters analysed during the 1994 Italian

championships.

The validity of postexercise lactate concentra-

tion as an indicator of the rate of anaerobic gly-

colysis was investigated in 400-m sprinting by

Lacouret al. (1990), and in 100-m and 200-m

sprinting by Hautier et al. (1994). In the study by

Lacouret al. (1990), blood samples were taken

Table 41.1Current world sprint records (as at January 1999).

Men Women

Distance (m) Time (s) Sprinter Time (s) Sprinter

100 9.84 D. Bailey 10.49 F. Griffith-Joiner

200 19.32 M. Johnson 21.34 F. Griffith-Joiner

400 43.29 H. Reynolds 47.6 M. Koch

Fig. 41.1Sprinters and hurdlers in training complete
prolonged sessions with many short efforts, even
though competitions may involve only a single sprint.
Photo courtesy of Ron Maughan.

50

40

30

20

10

0 20 40 60 80 100 120

10

7.5

5.0

2.5

0

Distance (m)

Phosphocreatine (mmol

.kg

–1

wt)

Speed (m

–1.s

)

Fig. 41.2Speed () and muscle phosphocreatine

concentration (
) during a simulated 100-m track

sprint (Hirvonen et al. 1987).