Falls are one of the major problems for elderly people and proprioceptive exercises have been suggested as an alternative in rehabilitation and preventive programs. The purpose of this study was to investigate the influence of a proprioceptive neuromuscular facilitation (PNF) exercise program on balance, knee extension and flexion isometric torque, and knee extension rate of force development (RFD). Fourteen older faller subjects (>60 years) were equally assigned into two groups: a control group (CG: ) and a training group (TG: ). The PNF training program was performed for 10 weeks on TG, with a frequency of three times per week. Patients were assessed before and after the PNF program, with respect to balance (Berg Balance Scale score—BBS), knee maximal isometric extension and flexion torque, knee extensor RFD, and knee extensors and flexors neuromuscular activation level and coactivation level around the knee. After 10 weeks, balance ( ) and knee extension torque ( ) were improved in TG while no differences were found for CG. These improvements were mainly attributed to central nervous system adaptations, since no differences were found for neuromuscular activation level and coactivation. 1. Introduction Falls in elderly are associated to both mortality and morbidly increasing. Falls are also the major death cause in people aging over 85 years [1]. Many tools were used to discriminate people on fall risk in the past. However, the most used by its low cost is the Berg Balance Scale [2, 3]. According to Lajoie and Gallapher [3] scores lower than or equal to 46 on Berg Balance Scale (BBS) classify subjects as fallers with 93% of specificity. Strength reduction is pointed as the major cause of falls in this population [4] and, therefore, maximal torque should be accessed on daily-life clinical tests. The center of mass or center of pressure dislocation and velocity are useful to discriminate subjects on fall risk [5]. However, these tests require expensive equipment and high advance knowledge. This problem is not observed on isometric contractions tests, where both the strength level and the quality of power production can be observed. This latter aspect had been studied by means of rate of force development [6–10]. Lower torque and power production on elderly fallers is associated with an increased coactivation around knee and ankle [1, 11]. Coactivation, defined as the simultaneous muscle contraction around a joint [12], had also being pointed as responsible to reduced walking speed and increase fall risk of elderly [13–15]. Beyond all exercise programs
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