Functional performance differences between carbon fiber and fiberglass prosthetic feet.

BACKGROUND: Persons with lower limb amputation require increased functionality. The largest category of feet for active individuals with a transtibial amputation is energy storage and return (ESR) feet. These feet are typically constructed of carbon fiber composite materials. Recently, a prosthetic foot composed of a fiberglass composite has emerged in the market. However, there are no comparative studies of these devices. OBJECTIVES: Compare the biomechanical performance and prosthesis-related quality of life when using a fiberglass prosthetic foot design compared with traditional carbon fiber ESR designs. STUDY DESIGN: This is a repeated-measures randomized cross-over trial. METHODS: Gait analysis was performed on 10 experienced male subjects with unilateral transtibial amputations (K-level III) while walking on level ground and a ramp. Patient-reported outcomes were collected using the Prosthesis Evaluation Questionnaire. RESULTS: Gait data demonstrated increased ankle dorsiflexion (P < .01), similar ankle moments (P = .07), and increased ankle power generation (P = .01) when using the fiberglass foot. The increased power generation occurred at the correct time in the gait cycle such that the timing and magnitude of peak knee flexion was unaffected (P > .19). The fiberglass foot had greater energy absorption during gait (P = .01) with no difference in energy return (P = .37). The subjects expressed improved prosthesis-related quality of life with the fiberglass foot (P = .01). CONCLUSIONS: The findings of this study demonstrate that the new ESR foot comprising a fiberglass material had better performance than traditional designs using a carbon fiber material.

The 'yips' in golf: a continuum between a focal dystonia and choking.

The definition of the 'yips' has evolved over time. It is defined as a motor phenomenon of involuntary movements affecting golfers. In this paper, we have extended the definition to encompass a continuum from the neurologic disorder of dystonia to the psychologic disorder of choking. In many golfers, the pathophysiology of the 'yips' is believed to be an acquired deterioration in the function of motor pathways (e.g. those involving the basal ganglia) which are exacerbated when a threshold of high stress and physiologic arousal is exceeded. In other golfers, the 'yips' seems to result from severe performance anxiety. Physically, the 'yips' is manifested by symptoms of jerks, tremors or freezing in the hands and forearms. These symptoms can result in: (i) a poor quality of golf performance (adds 4.9 strokes per 18 holes); (ii) prompt use of alcohol and beta-blockers; and (iii) contribute to attrition in golf. Golfers with the 'yips' average 75 rounds per year, although many 'yips'-affected golfers decrease their playing time or quit to avoid exposure to this embarrassing problem. While more investigation is needed to determine the cause of the 'yips', this review article summarises and organises the available research. A small study included in this paper describes the 'yips' phenomenon from the subjective experience of 'yips'-affected golfers. The subjective experience (n = 72) provides preliminary support for the hypothesis suggesting that the 'yips' is on a continuum. Based on the subjective definitions of 72 'yips'-affected golfers, the 'yips' was differentiated into type I (dystonia) and type II (choking). A theoretical model provides a guide for future research on golfers with either type I or type II 'yips'.