HEART-RATE DEFLECTION COMPARED TO 4MMOL-L(-1) LACTATE THRESHOLD DURING INCREMENTAL EXERCISE AND TO LACTATE DURING STEADY-STATE EXERCISE ON AN ARM-CRANKING ERGOMETER IN PARAPLEGIC ATHLETES

The deflection point (DP) of the heart rate in relation to the work ra te (WR) of 8 male endurance-trained paraplegics and 11 male physically active sports students was investigated during nonsteady-state increm ental arm cranking ergometry (IT) and compared to Introduction the 4 m mol.l(-1) blood lactate concentration threshold and to blood lactate c oncentration in steady-state exercise (SST). Heart rate, and lactate c oncentration from capillary blood, were determined at rest, during IT and SST. The DP was calculated by linear regression analysis of the he art rate during IT. The SST consisted of three consecutive exercise in tensities over a period of 8 min at exercise intensities of 10 W below , and at 10 W above the work rate at deflection point (WRDP) NO differ ence was found between the paraplegics and non-handicapped subjects re garding heart rate and blood lactate concentration at rest and during exercise. A DP was established in all the paraplegics and in 72.7% of the non-handicapped subjects, but lactate accumulation was observed in 75% of the paraplegics and in 62.5% of the non-handicapped subjects a t the lowest intensity of SST. In summary, endurance-trained paraplegi cs with an injury level below Tg showed heart rate and blood lactate c oncentration values comparable to non-handicapped subjects during IT. A linear increase at moderate exercise intensities and a levelling-off at higher to maximal intensities could be identified in all the parap legics and in 72.7% of non-handicapped subjects. The determination of the anaerobic threshold by DP should be applied with caution, since no causal relationship of DP and the anaerobic threshold was found and t he WRDP tended to overestimate threshold values.