previous balance training; a history of neuromuscular disorders, arthritis or rheumatologic disorders; systemic disease that might interfere with sensory input; or disorders of vision not correctable by glasses. Volunteers were randomly assigned to a training and control (CON) group and were requested to maintain normal training. Dynamic balance performance was assessed at baseline and then after 2 weeks and 4 weeks of progressive single-leg balance training. Within the training group, both the trained (TRD) and the untrained (UTD) legs were assessed at all time points. Furthermore, within the CON group, a single leg was assessed at all time points. The TRD leg was chosen at random, and in the CON group the leg assessed was also chosen at random. The SEBT offers a simple,

reliable, low-cost alternative to more sophisticated instrumented methods that are currently available to assess balance (7–9). It is a functional test that incorporates a single-leg stance on one leg with maximum reach of the opposite leg (Fig. 1). The SEBT was performed with the subject standing at the centre of a grid placed on the floor, with eight lines extending at 45° increments from the centre of the grid. The eight lines positioned on the grid were labelled according to the direction of excursion relative to the stance leg: anterolateral, anterior, anteromedial, medial, posteromedial, posterior, posterolateral and lateral. Subjects rode a stationary bike

for 5 minutes at a self-selected pace and then stretched the quadriceps, hamstrings and triceps surae muscle groups before testing. After the

FOLLOWING AS LITTLE AS 2–4 WEEKS OF PROGRESSIVE SINGLE-LEG DYNAMIC BALANCE TRAINING (TRD), SIGNIFICANT IMPROVEMENTS IN DYNAMIC BALANCE PERFORMANCE OCCURRED IN ALL DIRECTIONS OF THE SEBT

warm-up, each subject performed six practice trials for each leg in each of the eight directions in order to become familiar with the task, (7). A pilot study demonstrated that a minimum of three familiarisation trials was required in order to offset any learning, practice or warm-up effect.

In the testing phase, the subject

Figure 1: Subject performing the posterior reach component of the Star Excursion Balance Test

maintained a single-leg stance while reaching with the contralateral leg (reach leg) from an initial position next to the balance leg and then as far as possible along the appropriate vector. The subject was instructed to touch the farthest point on the line with the reach foot (toe only) as lightly as possible in order to ensure that stability was maintained through adequate neuromuscular control of the stance leg. The subject then returned to a bilateral stance. The examiner manually measured the distance in centimetres from the centre of the grid to the touch point with a tape measure. Three reaches in each direction were recorded. Subjects were given 15 seconds of rest between reaches. The best of the three reaches for each leg in each of the eight directions was recorded.

The leg tested (TRD, UTD), the order of excursions performed (clockwise, anticlockwise) and the direction of the first excursion (anterior, medial, lateral, posterior) were counterbalanced to control for any learning effect. Trials were discarded and repeated if the subject: n Did not touch the line with the reach foot while maintaining weight-bearing on the stance leg n Lifted the stance foot from the centre grid n Lost balance at any point n Did not maintain start and return positions for one full second.

The training group performed a range of manoeuvres that progressed from simple static balance exercises to more complex and challenging dynamic balance exercises (Table 1). Progression

8

and difficulty were developed by performing balance exercises with the eyes open and closed, on solid (gymnasium floor) and soft (thick gymnasium mat) surfaces, and with a range of contralateral limb and trunk movements performed while in a single-leg balance position.

The training group performed the exercises, in group sessions, 5 days a week for 4 weeks, commencing each workout with a 5-minute general cardiovascular warm-up and led by an experienced physiotherapist who was not involved in the SEBT testing. All subjects had balance performance assessments three times a week in order to promote exercise progression. Progression was based on the physiotherapist’s opinion of successful completion of all the movements with no loss of balance during each 60-second trial.

At baseline there were no

differences in reach distance, in any direction or for the total combined score, between the TRD and CON legs or between the TRD and UTD legs. The clear indication for total combined score and for individual directions was that reach distance increased significantly in the TRD leg at 2 weeks and then either remained greater than pre-scores (anterior, medial) or continued to significantly increase from 2 weeks to 4 weeks of training (total combined, anteromedial, posteromedial, posterior, posterolateral, lateral, anterolateral). For total combined and all individual directions, TRD leg-reach scores were significantly greater than CON leg-reach scores at both 2 weeks and 4 weeks. The percentage change from baseline to 4 weeks of training ranged from 10.7% to 35.5% in the anterior and anterolateral directions, respectively, in the TRD leg; changes in the CON leg over the same time period were always less than 4% and sometimes negative.

This study demonstrated that

following as little as 2–4 weeks of progressive single-leg dynamic balance

sportEX medicine 2009;41(Jul):7-10