Abstract
This study was conducted at the Physiotherapy Department, Faculty of Applied Medical Sciences, Umm Al- Qura University, Mecca, Saudi Arabia in 2018, to evaluate the effects of the smartphones on the hand grip strength, according to the hours of usage per day, and also the difference between males and females. 92 University students were randomly selected, with the elimination of pain or numbness in their hands. Demographic data were noted (age, weight, height, BMI, anthropometric measurements of the hand) and a questionnaire was given which contained the type of cell phone, the hand of dominance and hours of usage per day. The handheld dynamometer is an instrument that measures the force of muscle contraction was used to measure the hand grip strength of the dominant hand. The statistical results showed that with increased hours of usage in males there is an increase in hand grip strength, while the opposite was for females. The increase in hours of usage showed decreases in the hand grip strength. From the obtained results, it can be concluded that, male hand grip strength improved with increasing hours of smartphones usage, contrasting the females with as with increasing hours of usage the hand grip strength decreased.