It is clinically and practically relevant to note that the study demonstrated significant improvements in balance ability after a training period of only 2 weeks, which was further improved after 4 weeks in six of the eight directions. These findings appear to indicate that 2 weeks is sufficient time to promote significant improvements in dynamic balance ability that may be important for the maintenance of posture and balance (4), although the precise clinical impact in terms of injury prevention or motor function is impossible to determine. If more time is available to perform specific balance training, then improvements may continue to accrue, but probably at a reduced rate. It is not clear from this study or the existing literature how the gain in balance ability slows after an initial 4 weeks of training. The rapid improvement in balance

ability inside 2 weeks has practical implications and is important in time- limited training such as preseason training. The methods used are also easily transferable into the field, and the practical application of the current data in a clinical setting should be quite straightforward. The improvements observed in the UTD in some directions of the SEBT test provide new data to support that a crossover effect in balance ability is accruing from the TRD leg during the training sessions. The crossover effect has been described previously in a number of strength-training studies (16), and the percentage change in balance ability in the current study is very similar to that reported for strength development (16).

The importance of neural

mechanisms to explain this crossover effect has been reviewed (17,18). The crossover effect may have some implications for rehabilitation from athletic injury. Balance-training a non-injured leg could, in theory, lead to a small improvement in the injured leg, even if it were too early or inappropriate to balance-train the injured leg directly. An example of this has been demonstrated in shoulder injuries (19). Interestingly, the magnitude of the crossover effect may be direction-dependent, with greater effects occurring in transfer from the dominant to the non-dominant limb (20), which also has potential implications for the success of any

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crossover intervention in a clinical environment. In conclusion, as a result of only

2 weeks of progressive single-leg dynamic balance training, the reach performance of the TRD leg improved significantly across all directions of the SEBT test. Improvements continued to 4 weeks of training in six out of the eight directions employed in the SEBT protocol. Small but significant improvements in the UTD leg in four out of the eight directions of the SEBT test suggest some crossover training effect. The current training programme and test protocols can be transferred easily into the clinical environment to assess balance training and its impact upon function, injury and rehabilitation. This article was adapted from a study published in Physical Therapy in Sport and is reprinted with permission. A more detailed description of this study can be found in Rasool J, George K. The impact of single-leg dynamic balance training on dynamic stability. Physical Therapy in Sport 2007;8:177– 184.

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Jaffar Rasool, gained a BSc in Physical Therapy from King Saud University in 1994 and an MSc in Sports Injury from Manchester Metropolitan University in 2005. He is currently senior physiotherapist and education coordinator of the Physiotherapy Department in Qatief Central Hospital, Qatief, Saudi Arabia and works with the KSA (Kingdom of Saudi Arabia) national handball team and the AL Khaleej club.

THE AUTHOR Jaffar

TH in 2005. y Department in Qatief Central sportEX medicine 2009;41(Jul):7-10

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