A study on the effects of electronic games on musculoskeletal health and aerobic fitness in school-age children and adolescents

Abstract

Today school-age children and adolescents are exposed to a wide range of screen-based devices, particularly various electronic games (EG) systems. High exposure and intensive use of these devices may have negative health impacts on the musculoskeletal system and aerobic fitness. The purposes of this thesis were: a) to examine the pattern of EG device usage, sedentary behaviours and physical activities among school-age children and adolescents, and their association with musculoskeletal discomforts (MSDs); b) to investigate the biomechanical loading and the oxygen consumption during play of two types of EG devices (small-screen handheld and active game system), as well as MSDs and aerobic fitness related to EG play. This thesis involves two studies. Study 1 involved a survey on the usage of EG devices among Primary 4 to Secondary 3 students of four schools in Hong Kong. The survey was conducted from November 2009 to May 2010. Two primary and two secondary schools participated, returning 1,590 questionnaires (out of 2,000, the response rate was 79.5%) for analysis. The mean age of the 1,590 children surveyed was 12.49±2.03 years and the age range was 8-18 years; 23.7% reported high-level use of EG devices (more than four hours daily), and amongst these high-level EG device users, more boys were large-screen based device users while small-screen handheld devices were used by more girls. More secondary school students were associated with the habit of high-level EG use than primary school students (32.2% versus 9.3%). The survey found students spent long hours (≥4 hrs/day) in computer use (30.7%) and television viewing (27.2%). Only 18% of students had a habit of physical activity more than 60 minutes daily. Participants were asked to indicate their bodily discomfort related to EG play. 19.5% and 23.8% of students had neck discomfort and upper limb discomfort, respectively. Univariate logistic regression analysis of the data illustrated that high EG use (≥4 hrs/day) was associated with neck discomfort (odds ratio=1.400, 95% CI=1.083-1.811, p=0.010) and upper limb discomfort (odds ratio=1.687, 95% CI=1.307-2.177, p=0.001). Study 2 investigates the biomechanical loading on the musculoskeletal system (Part A) and on oxygen consumption (Part B) during play sessions with two types of EG devices: the small-screen handheld Sony PlayStation Portable® (PSP) and the active game system the Nintendo Wii® (Wii), in the same group of subjects (aged 10-14 years). Specifically, Part A examined in 36 subjects, the electromyographic and kinematic responses of the neck and upper limb region during 20 minutes of EG play, and its association with subjective musculoskeletal discomforts. Surface electromyography (EMG) was conducted to measure the muscle activity of the cervical erector spinae (CES), upper trapezius (UT), extensor carpi radialis (ECR), flexor carpi ulnaris (FCU), and abductor pollicis brevis (APB). Head-neck angle and wrist joint movements (posture and angular acceleration) were measured by inclinometer and 2-D electrogoniometers, respectively. The results showed that there was constantly high loading to the CES during EG play, possibly due to the need to stabilize the head in a flexion posture during PSP play. The variability of ECR and FCU muscle activity and the range of wrist movement were very low, suggesting static muscle tension and static wrist posture. During Wii play, which involves more dynamic arm movements, maintaining the head in an erect posture and high neck muscle activity were recorded. The high ECR and FCU activity and high wrist angular acceleration could be beneficial to young people as this may promote musculoskeletal development in the forearm. Part B of the study involved indirect calorimetric measurement of oxygen consumption during a play session with the PSP and Wii in the same group of subjects. Subjects' maximal aerobic capacity (VO2max) was estimated by a submaximal stress test - the ‘three-minute step test'. Results of this study showed that the physical activity level of playing both games were less than 3 metabolic equivalents (METs) thus the physical activity level is "light". The estimated VO2max were compared by the effect of high-level (≥4 hrs/day) and low-level (<4 hrs/day) of EG devices usage and the results were not significant. In conclusion, the findings of this study show school-age children and adolescents have a daily habit of intensive EG use. The results of the experimental studies confirm a sustained poor neck flexion posture, and with high static muscle loading to the neck and upper limb regions during small-screen handheld EG use. Playing a Wii game is considered by some to be an active exercise; however, its energy cost does not meet the recommended guidelines for the healthy growth of young people. The work of this thesis provides preliminary evidence relating to the impact of EG playing on the musculoskeletal health and aerobic fitness of children and adolescents. This useful information may contribute towards the development of ergonomic guidelines for school-age children and adolescents during the use of EG devices. Further research should investigate the cause-and-effect relationship among the EG devices use, bodily discomfort, and the musculoskeletal responses.