This study examined the effects of the level of spinal cord injury upon the thermoregulatory responses of wheelchair athletes during prolonged wheelchair exercise in warm conditions. Eight tetraplegic (TP), 10 high-level paraplegic (HP), and 10 low-level paraplegic (LP) athletes exercised for 60 min at 60% JOURNAL/mespex/04.02/00005768-200307000-00023/ENTITY_OV0312/v/2017-07-20T222913Z/r/image-pngO2peak in a warm environment (31.5 ± 1.7°C, 42.9 ± 8.0% relative humidity). Skin temperature and aural temperature were monitored. Aural temperature increased gradually during the exercise period by 1.1 ± 0.3 and 1.4 ± 0.5°C for the HP and LP groups, with a more marked increase observed for the TP group (2.1 ± 0.5°C; P < 0.05). Upper-arm skin temperature was higher for the TP when compared with the HP and LP between 30 and 60 min (P < 0.05). Back skin temperature was higher for the TP when compared with the HP and LP between 45 and 60 min (P < 0.05). No differences were noted between groups for the thigh or calf skin temperatures. During recovery, skin temperature remained elevated for the TP group when compared with the HP and LP groups (P < 0.05). Heat storage was greatest for the TP athletes at the end of exercise and remained elevated throughout recovery (P < 0.05). All athletes completed the exercise task even though the gradual increase in aural temperature observed for the HP and LP groups suggests a degree of thermal imbalance. However, this was much less than observed for TP athletes, who demonstrated a much greater imbalance in temperature regulation. Increasing the exercise or environmental strain may result in the thermoregulatory responses of athletes with a spinal cord injury being compromised.

The aim of this study was to determine the effects of sodium bicarbonate ingestion on prolonged intermittent exercise and performance. Eight healthy male subjects (mean +/- SD: age 25.4 +/- 6.4 yr, mass 70.9 +/- 5.1 kg, height 179 +/- 7 cm, VO(2max) 4.21 +/- 0.51 L.min-1) volunteered for the study, which had received ethical approval. Subjects undertook two 30-min intermittent cycling trials (repeated 3-min blocks; 90 s at 40% VO(2max), 60 s at 60% VO(2max), 14-s maximal sprint, 16-s rest) after ingestion of either sodium bicarbonate (NaHCO(3); 0.3 g.kg-1) or sodium chloride (NaCl; 0.045 g x kg(-1). Expired air, blood lactate (BLa), bicarbonate (HCO(3)-), and pH were measured at rest, 30 and 60 min postingestion, and during the 40% VO(2max) component of exercise (4, 10, 16, and 29 min). After ingestion, pH increased from rest to 7.46 +/- 0.03 and 7.40 +/- 0.01 for NaHCO(3) and NaCl, respectively (main effect for time and trial; P < 0.05). Values decreased at 15 min of exercise to 7.30 +/- 0.07 and 7.21 +/- 0.06, respectively, remaining at similar levels until the end of exercise. BLa peaked at 15 min (12.03 +/- 4.31 and 10.00 +/- 2.58 mmol.L-1, for NaHCO(3) and NaCl, respectively; P > 0.05) remaining elevated until the end of exercise (P < 0.05). Peak power expressed relative to sprint 1 demonstrated a significant main effect between trials (P < 0.05). Sprint 2 increased by 11.5 +/- 5% and 1.8 +/- 9.5% for NaHCO(3) and NaCl, respectively. During NaHCO(3), sprint 8 remained similar to sprint 1 (0.2 +/- 17%), whereas a decrease was observed during NaCl (-10.0 +/- 16.0%). The results of this study suggest that ingestion of NaHCO(3) improves sprint performance during prolonged intermittent cycling.

Athletes with spinal cord injury (SCI), and in particular tetraplegia, have an increased risk of heat strain and consequently heat illness relative to able-bodied individuals. Strategies that reduce the heat strain during exercise in a hot environment may reduce the risk of heat illness. To test the hypotheses that precooling or cooling during intermittent sprint exercise in a heated environment would attenuate the rise in core temperature in tetraplegic athletes, eight male subjects with SCI (lesions C₅–C₇; 2 incomplete lesions) undertook four heat stress trials (32.0 ± 0.1°C, 50 ± 0.1% relative humidity). After assessment of baseline thermoregulatory responses at rest for 80 min, subjects performed three intermittent sprint protocols for 28 min. All trials were undertaken on an arm crank ergometer and involved a no-cooling control (Con), 20 min of precooling (Pre), or cooling during exercise (Dur). Trials were administered in a randomized order. After the intermittent sprint protocols, mean core temperature was higher during Con (37.3 ± 0.3°C) compared with Pre and Dur (36.5 ± 0.6°C and 37.0 ± 0.5°C, respectively; P < 0.01). Moreover, perceived exertion was lower during Pre (13 ± 2; P < 0.01) and Dur (12 ± 1; P < 0.01) compared with Con (14 ± 2). These results suggest that both precooling and cooling during intermittent sprint exercise in the heat reduces thermal strain in tetraplegic athletes. The cooling strategies also appear to show reduced perceived exertion at equivalent time points, which may translate into improved functional capacity.

Purpose: Individuals with a spinal-cord injury have impaired thermoregulatory control due to a loss of sudomotor and vasomotor effectors below the lesion level. Thus, individuals with high-level lesions (tetraplegia) possess greater thermoregulatory impairment than individuals with lower-level lesions (paraplegia). Previous research has not reflected the intermittent nature and modality of wheelchair court sports or replicated typical environmental temperatures. Hence, the purpose of this study was to investigate the thermoregulatory responses of athletes with tetraplegia and paraplegia during an intermittent-sprint protocol (ISP) and recovery in cool conditions.Methods: Sixteen wheelchair athletes, 8 with tetraplegia (TP, body mass 65.2 ± 4.4 kg) and 8 with paraplegia (body mass 68.1 ± 12.3 kg), completed a 60-min ISP in 20.6°C ± 0.1°C, 39.6% ± 0.8% relative humidity on a wheelchair ergometer, followed by 15 min of passive recovery. Core temperature (T_core) and mean (T_sk) and individual skin temperatures were measured throughout.Results: Similar external work (P = .70, ES = 0.20) yet a greater T_core (P < .05, ES = 2.27) and T_sk (P < .05, ES = 1.50) response was demonstrated by TP during the ISP.Conclusions: Despite similar external work, a marked increase in T_core in TP during exercise and recovery signifies that thermoregulatory differences between the groups were predominantly due to differences in heat loss. Further increases in thermal strain were not prevented by the active and passive recovery between maximal-effort bouts of the ISP, as T_core continually increased throughout the protocol in TP.