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Michael et al.

5

demonstrates the kayak paddlers’ ability to withstand high levels of arm exercise before fatigue sets in.

Anaerobic power of paddlers Tesch (1983) suggested that the elite paddlers examined in his study exhibited a well developed anaerobic capacity for upper-body exercise. The relatively high peak blood lactate concentration values observed following maximal kayak racing (13 mM; Tesch, 1983) indicate a significant anaerobic contribution to kayak performance (Bishop,

  • 2000)

    (Table 4). It was suggested by Pendergast et al.

  • (1979)

    that the kayaker paddlers were capable of develop-

ing at least twice the anaerobic power of sedentary sub- jects for arm cranking exercises. In light of this however, Pyke et al. (1973) suggested that to assess the physiologi- cal responses to work by kayakers, the circular movement of hand/arm cranking on an ergometer does not closely simulate the movements required on the water. It is es- sential to utilise specific ergometers to allow for an accu- rate comparative analysis.

Associated with the results presented above, were the findings presented by Davis et al. (1976) and Tesch and Lindeberg (1984) who reported kayakers to have lower blood lactate levels during similar absolute exercise intensities or work loads relative to maximal oxygen uptake when compared to sedentary subjects performing arm exercise. Therefore, as previously mentioned by Tesch (1983), in kayaking and numerous other sporting events that require high aerobic energy supply, the an- aerobic energy system seems to be an important factor for successful performance.

To compare the lactate levels among a number of different sporting athletes Tesch and Lindeberg (1984) studied 7 elite male kayak paddlers, 6 national calibre weight/power lifters, 8 local and national calibre body builders and 6 physically active non athletes. All subjects performed upper body exercise seated on an arm crank ergometer. Results suggested that the kayakers exhibited a significantly lower blood lactate concentration (p < 0.05) at all power outputs tested. The authors suggested that factors other than muscle volume determined the rate of blood lactate accumulation during progressive arm exer- cise. This was most evident when comparing the lactate response in the kayak paddlers (endurance trained ath- letes) with that of the strength trained athletes, who exhib- ited significantly greater upper body mass. Similarly, lower blood lactate levels were reported by kayak pad- dlers than their sedentary subject counterparts during comparable absolute or relative work loads. It was sug-

gested by Pendergast recorded when measuring

et the

al. (1979) that low values lactate of kayakers was a

result of a relatively high early lactate threshold and thus

a decreased release of lactate (relative to sedentary sub- jects) from trained muscle performing the submaximal work. As the work intensity increased, the kayakers were more able to perform aerobically for a longer period of time, therefore delaying the onset of blood lactate accumulation.

When five moderately active subjects underwent a month of kayak training, Ridge et al. (1976) reported a significant reduction (up to a 6%) in the level of blood lactate accumulated at the same relative work loads on the kayak ergometer compared to the pre-test. Furthermore, training has also shown to decrease the arterial lactate for a given exercise load in the study by Klassen et al. (1970). The data presented by Klassen et al. (1970) reflects a training-induced decrease in overall release of lactate from tissues to blood as well as an increase in clearance of lactate from plasma during exercise. The muscular lactate clearance reflects a reduction in glycogenolysis and enhanced muscle enzyme capacity (Bergman et al., 1999; Stallknecht et al., 1998). An enhanced lactate trans- port capacity in the muscle has also been suggested to contribute to the high clearance following training (Brooks et al., 1999).

Conclusion

Elite male kayakers appear homogeneous in shape and physical size, being differentiated from the general popu- lation by their greater upper body girth and narrow, hips (Ackland et al., 2003) and demonstrate superior aerobic and anaerobic qualities (Hahn et al., 1988; Tesch et al., 1976; Tesch, 1983; Pendergast et al., 1989; Zamparo et al., 1999). Kayakers have reported VO2peak values of around 58 ml·kg-1·min-1 (4.7 L·min-1) and lactate values of around 12 mM during laboratory and on water testing. For kayaking, a sport that relies on high maximal aerobic power, the anaerobic energy system also seems to be important for successful performance. van Someren and Oliver (2001) reported that the mean lactate threshold occurred at a blood lactate concentration of 2.7 mmol·L-1, at a HR of 170 beats·min-1 and a VO2 of 44.2 ml·kg-1·min- . The lactate threshold presented corresponded to a per- centage of 89.6% of the maximum heart rate and 82.4% of the VO2 peak. 1

Although the absolute values of peak VO2for kay- aking have been described to be quite high (Tesch, 1983), they are not quite as high as other sporting events such as road cycling, rowing or running. Billat et al. (1996) showed on the kayak ergometer, the power output of kayak paddlers at VO2peak was only 57% of the power output produced by cyclists on their respective ergometer. In other sports, such as road cycling and distance running

Table 4. Lactate values recorded for kayak paddlers (mM).

Author Sidney and Shephard, 1973

Subjects 10 elite kayakers

Tesh et al. 1976 Tesch, 1983 Pendergast et al. 1989 Bishop et al. 2002

6 elite kayakers 6 elite kayakers 17 kayakers (range of skill level) 8 experienced kayak paddlers

Leg

Arm

Kayak

14.1

14.2

13.5

14.0

Ergometer (mM) .

13.2

12.9

13.0

13.0

12.0

Kayak paddling (mM)

500m

1000m

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