Running Prosthesis Facilitates Greater Speed, Peak Aerobic Capacity, And Improved Exercise Economy In Amputee Runners

Abstract

Amputees may have greater energy cost than non-amputees when walking at comparable speed. Although improvements in prosthetic technology have facilitated participation in competitive running, the impact on physiological responses during running has not been examined. PURPOSE: To compare physiological responses of lower-extremity amputee (AMP) running-specific prosthesis (RP) versus a non-running specific prosthesis (NRP) and cross-referenced with non-amputee controls (C) matched by training status, age, and body composition during level treadmill running. METHODS: Six highly-trained male runners served as subjects. AMP subjects were bilateral (n= 1) and unilateral (n=2) who had experienced > 4 yr of limb loss due to trauma. AMP and C were similar in age (33.3 ± 9.8, 33.0 ± 10.4yr), height (177.0 ± 8.9, 178.6 ± 3.07 cm), weight (79.8 ± 7.5, 76.3 ± 4.8 kg), and % body fatness as assessed by dual energy X-ray absorptiometry (15.7 ± 6.3, 16.0 ± 5.5 %fat). Subjects completed 5-min submaximal treadmill bouts during which heart rate (HR), ratings of perceived exertion (RPE) and oxygen uptake (VO2) were obtained. AMP performed two of their submaximal bouts with: 1) running-specific prosthesis (RP), and 2) non-running specific prosthesis (NRP). Following the submaximal test, C and AMP (with RP) performed a continuous speed-incremented maximal treadmill test until volitional fatigue. RESULTS: During submaximal running at 132 m/min, NRP elicited significantly greater (p< 0.05) HR (by 30 bts/min) and VO2 (by 8 ml/kg/min) compared to RP in AMP. Compared to matched C, this elevation in HR and VO2 was similar (by 22 bts/min and 5 ml/kg/min). HR and VO2 at 132 m/min were not significantly different from C when AMP used RP. AMP and C achieved similar peak HR (186 ± 3.5, 182 ± 2.5 bts/min), VO2peak (50.7 ±9.1, 55.0 ± 87 ml/kg/min), VO2peak relative to fat free mass (63.1 ±4.6, 65.6 ± 3.6 ml/kg/min), and peak treadmill speed (240.0 ± 28.2, 268.2 ± 22.8 m/min, respectively). CONCLUSIONS: RP permits AMP to attain similar peak treadmill speed and aerobic capacity as matched non-amputees and significantly attenuates cardiovascular strain and energy cost of submaximal running compared to NRP.