Exercise testing and training in people with Huntington's disease

OBJECTIVE

To explore exercise response in people with Huntington's disease (HD).

DESIGN

Experimental observational study with a randomly allocated subgroup before/after interventional study.

SETTING

Community.

SUBJECTS

People with HD (n=30) and a healthy comparator group (n=20). Thirteen people from the HD group were randomly allocated to an exercise training program.

MAIN MEASURES

Heart rate (HR) and perceived exertion on the Borg-CR10 scale (RPE) during a submaximal cycle ergometer exercise test (three minute unloaded and nine minute 65%-75%HRmaximum phase). Expired air and lactate measures were available for 8 people with HD during the exercise.

INTERVENTION

A 12 week gym and home walking exercise programme (n=13).

RESULTS

People with HD achieved a lower work rate at nine minutes (82±42(0-195) v 107±35(50 -185) Watts (p<0.05)), but higher RPE at both three (3±2(0-7) v 1±1(0-4)) and nine minutes (7±3(1-10) v 5± 2(2-9)) both p<0.01, compared to the healthy group and did not achieve a steady state HR during unloaded cycling. People with HD also demonstrated higher than expected lactate at three 2.5±2.5(1.1-8)mmo.L-1 and nine 3.8±1.9(1.2-6.6)mmo.L-1 minutes and respiratory exchange ratio at three 0.78±0.03 (0.74-0.81) and nine minutes 0.94±0.11(0.81-1.15). After exercise training there were no changes observed in HR or RPE responses during the exercise test.

CONCLUSIONS

There was a large variability in the observed metabolic and physiological responses to exercise in people with HD. The observed exercise responses suggest that altered exercise prescription parameters may be required for people with HD and that exercise response and factors' affecting this requires further investigation.

Self-esteem and coping responses of athletes with acute versus chronic injuries

Self-esteem and coping strategies have been important factors in athletes' response to injury and subsequent rehabilitation. Specifically, athletic injury has been negatively associated with self-esteem, while certain coping strategies may enhance adherence to rehabilitation (1, 4). Little is known, however, concerning the effect of acute (sudden specific event) versus chronic injury (repetitive injury over a prolonged period of time) on self-esteem and coping strategies. The Rosenberg Self-esteem Inventory (3), selected subscales of the Ways of Coping Questionnaire (2), and a demographic questionnaire were administered. The subscales of Ways of Coping Questionnaire employed were Seeking Social Support, Accepting Responsibility for the injury, and Escape Avoidance of the injury. To assess the influence of acute versus chronic injury status, effect sizes (ES) were calculated. Although no difference was found for Accepting Responsibility, chronically injured athletes scored higher on Escape/Avoidance (M = 2.4 vs 1.9, SD = 1.2 vs .6, ES = .52) and lower on Seeking Social Support (M = 2.5 vs 2.8, SD = .6 vs .4, ES = .47) than athletes with acute injuries. Those with chronic injuries also second more negatively on self-esteem (M = 6.2 vs 4.4, SD = 1.2 vs 1.2, ES = 1.30) than acutely injured athletes. These preliminary results suggest the type of injury may differentially affect self-esteem and coping behavior. As self-esteem is theorized to be relatively stable construct, it is perhaps not surprising that chronic injuries have a greater effect than acute injuries. Chronically injured athletes also sought social support less and engaged in more escape/avoidance behavior, suggesting that they cope with injury differently than those with acute injuries.