Abstract des Autors

This paper is aimed a) to extend the data base on the cardiorespiratory adjustments and on the level of physical fitness of spinal cord injury (SCI) subjects living in Italy, a country where participation in social and community activities is still quite difficult for wheelchair-dependent individuals, and b) to evaluate the role played by training condition in respect to the role of injury levels in determining the maximal attainable performance capacity. A total of 24 male SCI were selected as follows: elite marathon racers with T1-T4 (n=4; 23-28 yrs; 49-65 kg BW) and T7-L2 (n=4, 22-30 yrs, 59-67 kg BW) injury levels; T7-L2 moderately trained SCI basketball players (n=16; 27+/-1(SE) yrs, 70+/-3.4 kg BW). A group of age- and gender-matched sedentary able bodied individuals acted as controls. Oxygen consumption (VO2), pulmonary ventilation (VE) and heart rate (HR) were measured at the last min of 3-5 submaximal exercises of increasing intensities, each lasting 7 min, and at exhaustion (peak values, p), during wheelchair roller ergometer locomotion. Blood lactate concentration [LA] was also determined at the 5th min of recovery. During submaximal exercise HR/VO2 relationship increased linearly in all individuals with quite different slopes: in marathon racers at a VO2 = 1500 ml/min HR was almost maximal in T1-T4, and reached 120-140 b/min in T7-L2. In T7-L2 moderately trained SCI a VO2 = 800 ml/min was accompanied by a HR ranging between 90 and 140 b/min (in controls between 95 and 120 b/min). VE was considerably different among subjects for a given VO2. At exhaustion VO2p and VEp per kg and [LA]p were extraordinarily high for the small muscle mass activated. In T1-T4 marathon racers VO2 was 31+/-4 ml/min, VE 1184+/-102 ml/min and [LA] 7.2+/-2 mmol/l and, respectively, 43+/-2 ml/min, 1735+/-161 ml/min and [LA] 13+/-1 mmol/l in T7-L2. On the contrary, in the moderately trained basketball SCI and controls, 50% lower values were observed. When VO2p values were evaluated as a function of the injury level in SCI with similar training condition, and the data from the literature were also taken into account, practically no changes occurred from L2 to T6. On the contrary from T6 to C6 a dramatic VO2p decrease was observed, reaching at C6 injury level a value about 50% lower. In conclusion, intense aerobic training increases the maximal capacity to perform exercise up to the double of the value of untrained SCI subjects with the same injury level. The level of injury impairs the maximal performance mainly above T6 where certain autonomic reflexes required for normal responses to exercise are disrupted. Verf.-Referat