A predictive model to quantify joint torques and support reaction forces when using a smartphone while standing with support

Postural prevalence, time of day and spent time activities during smartphone weekday use among students: A survey to prevent musculoskeletal disorders

The long time spent on smartphones in awkward postures exposes young users to the risk of developing musculoskeletal disorders (MSDs). This study aimed to investigate 1) how the duration of smartphone use varies by the time of day and activities and 2) the risks of MSDs based on an analysis of the postures used when interacting with smartphones. A cross-sectional survey was conducted among 263 university students. The duration of smartphone use during a typical weekday was investigated over four times of the day and seven activities. After checking for normality, a nonparametric Friedman test was used to study the differences in the time spent using a smartphone according to the time of day and activity. Postural prevalence during weekdays was analyzed using a taxonomy called SmarTaxo, consisting of 41 postures. The Rapid Upper Limb Assessment (RULA) ergonomic score was chosen to assess the MSD risks associated with each posture. Smartphone use was the highest in the evening (301.1 min; 95 % confidence interval [CI]: 277.4-324.8 min, p < 0.05). Texting (170.8 min; 95 % CI: 152.0-189.6 min) and watching videos (163.6 min; 95 % CI: 146.3-180.9 min) were the most common activities. Three sitting and two walking postures were primarily used in the morning (29.3-36.9 %), afternoon (27.0-44.4 %), and evening (28.9%-38.9 %). Standing postures were preferred in the morning and afternoon (36.9 % and 42.2 %, respectively), while one lying posture was widely reported in the evening (39.2 %). The RULA scores for these postures ranged from 3 to 4. However, four lying postures, often observed during the evening (frequency between 20.5 % and 37.6 % of the time), had RULA scores of 6. In conclusion, the study identified an existing MSD risk among smartphone users, especially with long durations of daily use. Special emphasis should be placed on addressing the reclining postures adopted during evening smartphone use, as they subject students to a significantly elevated risk of MSDs.

Effect of day time on smartphone use posture and related musculoskeletal disorders risk: a survey among university students

BACKGROUND

Musculoskeletal disorders (MSDs) are one of the most important problems among young smartphone users worldwide. Portability leads to a wide variety of postures during the different activities of the day. The objective evaluation of these postures coupled with ergonomic tools allows evaluating the level of MSD risk to which users are exposed.

METHODS

The purpose was to investigate the effect of the time of day on the posture adopted during smartphone use among university students. The study was conducted through a cross-sectional survey of 263 university sports students. Four time of day, i.e. morning, afternoon, evening and night, and a taxonomy of 41 postures called SmarTaxo were considered. SmarTaxo included 18 sitting, 11 standing, 10 lying and 2 walking postures and their ergonomic score. After checking the normality of the data, a non-parametric Kruskal-Wallis test was used to study the effect of the time of day on the use duration of the different postures.

RESULTS

The total mean duration use per typical weekday was 5.39 ± 2.19 h for males and 5.15 ± 1.60 h for females with maximal duration during evening. The average smartphone use durations were statistically longer in afternoon and evening for all sitting (9.44 and 9.22 min respectively, p < 0.05) and calling (3.38 and 3.33 min respectively, p < 0.05) postures. The longest duration for standing postures was recorded for afternoon (8.91 min, p < 0.05). The lying postures were significantly more present in evening (19.36 min). Some postures were more used during a time of day. The side-lying posture was used more in evening and has an ergonomic score of 6, i.e. a high MSD risk.

CONCLUSIONS

The survey showed that users are exposed to MSDs regardless of posture and time of day. Sitting postures are used more in the morning and afternoon while lying postures are used more in the evening. As long as the rate of use is so high (> 5 h per day), young people will remain highly exposed to MSDs.