Strength, and proprioception training of upper body following injuries is commonly recommended. However, there are no previous studies investigated the effects of Biodex balance training on the strength, stability and function of the upper quarter. So, the purpose of this study will investigate the effect of Biodex balance training on improving the strength, dynamic stability and function of the upper quarter in young recreational weightlifters.

Study design This is randomized controlled study. There are two groups classified randomly (group A & group B); group (A); will receive upper extremities biodex balance training. 3 times/week for 8 weeks and group B that receive no treatment just assessment pre and post. Both groups will receive their regular weightlifting training exercises 4times/week.

Procedures Testing procedures Data collection from the testing procedures in the pre and post interventional phase will take place over two days to avoid the impact of fatigue on the participants' physical performance. In the first day, descriptive data will be measured and recorded for each subject including age, height, weight, upper extremity dominance (defined as the hand reported to be preferred for ball throwing). This will be followed by the upper quarter Y- balance (UQ-YBT) and the Dynamic limits of stability (DLOS) using the Biodex balance system. In the second day, data will be collected from the 2-minutes 90° push-up test and the one-arm hop test. The order of days and testing procedures will be randomized for all participants.

Training procedure Total number of 24 training sessions will be scheduled to the participants in group A over a period of eight weeks (three sessions/week). The Rating of perceived exertion (RPE) or Modified Borg scale (MBS) was used to monitor and guide exercise intensity. The scale allowed participants to subjectively rate their level of exertion during training. It starts at number 0 where training is causing no breathing difficulty at all and progress through to number 10 where breathing difficulty is maximal. Training will start with the current level of balance of each participant at which he reports exertion level of ≥ 5 based on modified Borg scale and progressed towards the more difficult ones. The Biodex display screen will be connected to a computer screen that will be positioned at a level to allow visual feedback to the participants during training The transition from one level to the more difficult one will be based on composite score of > 95% at the present level. Each training session will consist of three minutes training and one-minute rest, repeated for a total of 20 minutes.

Inclusion Criteria:

• Healthy recreational male weightlifters aged between 19 and 25 years

Exclusion Criteria:

• if they took any hormonal supplements, participated in professional bodybuilding or power lifting competition, had shoulder pain or history of surgery or musculoskeletal injuries and if they dropped out their gym workout for more than three weeks in the last six months.

A fifty male weightlifters