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| ORIGINAL ARTICLE |
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| Year : 2022 | Volume
: 7
| Issue : 2 | Page : 266-270 |
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Alterations of hand muscle strength in children due to schoolbag carriage
Ruchira Mukherjee1, Koumi Dutta2, Devashish Sen1, Subhashis Sahu2, Aparna Mukhopadhyay1
1 Department of Life Sciences, Presidency University, Kolkata, India
2 Department of Physiology, University of Kalyani, Kalyani, West Bengal, India
| Date of Submission | 11-Feb-2022 |
| Date of Acceptance | 14-Mar-2022 |
| Date of Web Publication | 13-Jul-2022 |
Correspondence Address:
Aparna Mukhopadhyay
86/1 College Street, Presidency University, Kolkata - 700 073, West Bengal
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/bjhs.bjhs_31_22
BACKGROUND: Heavy schoolbag carriage induces pain and fatigue in children. It can alter the handgrip strength (HGS) in children – an important parameter given that most activities in school curriculum require hand dexterity. The purpose of this study is to explore if and how schoolbag carriage influence HGS in children.
MATERIALS AND METHODS: Twenty-five healthy male participants (10–15 years) walked without schoolbag (0% load of bodyweight) or with schoolbags (weighing 4%, 8%, 12%, or 16% of their bodyweight) for 20 min on plane surface at preferred pace. The number of steps taken during walk was measured using pedometer. HGS was measured before and after each walk using dynamometer. The heart rate during walk was measured using Polar HR monitor. Pain occurrence in the entire body was mapped.
RESULTS: HGS averaged for both hand decreased from 17.8 (±6.72) kg to 17.3 (±6.28) kg after 20-min walk (P = 0.033, paired sample t-test). The adopted speed and heart rate was higher when carrying a schoolbag but it portrayed no significant association with HGS. Occurrence of shoulder pain significantly associated with increasing in HGS of right hand after walking (Phi coefficient = 0.21[P = 0.030]). If shoulder pain was perceived during walk, there was a 2.5 times higher likelihood that the participants' HGS for right hand increased (odd's ratio = 2.515, 95% confidence interval = 1.086–5.825).
CONCLUSION: Schoolbag carriage reduces HGS in children. Therefore, performing upper body conditioning exercises may help ameliorate the ill effects of heavy backpack carriage.
Keywords: Children, dynamometer, odd's ratio, Phi coefficient, physical activity
How to cite this article:
Mukherjee R, Dutta K, Sen D, Sahu S, Mukhopadhyay A. Alterations of hand muscle strength in children due to schoolbag carriage. BLDE Univ J Health Sci 2022;7:266-70 |
How to cite this URL:
Mukherjee R, Dutta K, Sen D, Sahu S, Mukhopadhyay A. Alterations of hand muscle strength in children due to schoolbag carriage. BLDE Univ J Health Sci [serial online] 2022 [cited 2023 Jun 8];7:266-70. Available from: https://www.bldeujournalhs.in/text.asp?2022/7/2/266/350880 |
Education in India follows a “textbook culture” where prescribed textbooks for each subject hold central place in the system.[1] Carrying numerous textbooks increase the weight of schoolbags. The recommended schoolbag load, 10%–15% of bodyweight,[2] is seldom adhered to[3] and reportedly has derogatory physiological effects.[4],[5] Hence, it is essential to explore schoolbag carriage with loads lesser than, within, and above this 10%–15% limit. Heavy schoolbag carriage may culminate in the development of low-back pain, changed spinal curvature, and a multitude of musculoskeletal symptoms.[6],[7],[8]
Schoolbag carriage causes pain in upper body parts such as neck, back, and shoulders,[9] also, prolonged carriage can induce fatigue.[10] The physical activity of schoolbag carriage for 30 min induced fatigue in 51% of the participants.[11] Fatigability and severity of muscle fatigue can be assessed by repeated measurements of handgrip strength (HGS).[12] It has been reported that significantly reduced HGS may indicate muscle and fatigue-related symptoms.[13]
HGS is not only a measure of upper body strength but also a screening tool for overall strength. Repeated measures of HGS indicate performance and overall health. HGS is not only subject to muscle fatigue but also pain sensations in neck, back, and shoulder. The reports of HGS and pain are ambiguous. While some reports suggest that HGS decreases with pain sensations in neck,[14] back,[9] and shoulder regions,[15] other reports suggest positive or no association.[16],[17],[18] HGS is affected by pain and fatigue thus encompassing the major outcomes in the physiological cost of schoolbag carriage.
HGS is an especially important parameter for schoolchildren because most activities in curriculum such as writing, playing musical instruments, sports such as basketball, badminton, arts and crafts all need hand dexterity. The alterations in HGS due to backpack carriage have been studied in adults (mean age-26 years).[19] There is a lacuna when it comes to studies on HGS changes due to schoolbag carriage in children. The aim of this study was to identify if the physical activity of schoolbag carriage alters the HGS in children and its association with pain occurrence, subsequently exploring the newfound association qualitatively and quantitatively.
| Materials and Methods | |  |
The study was conducted among 25 healthy male participants (randomly taken), belonging to the age group 10–15 years, in West Bengal, India, after obtaining signed consent forms from their legal guardians. Subjects with any congenital and/or musculoskeletal disorder were excluded from the study. The study was approved by the Institutional Ethical Committee (Human) and all data collection were done in accordance to the Declaration of Helsinki.
Each participant was asked to walk at their preferred pace for 20 min either without a schoolbag (0% load of bodyweight) or with a schoolbag (weighing 4%, 8%, 12%, and 16% of their respective bodyweight). The same ergonomically designed schoolbag was placed at the mid-back region for all the participants. Each participant had to walk 20 min/day for 5 consecutive days bringing the total number of walks to 125. Complying with research ethics, whenever a participant complained of pain, excessive fatigue, or breathlessness, the walk was stopped immediately. Some participants also dropped out without completing all 5 walks. Finally, 101 complete walks were considered in the study (n = 101). Temperature (not exceeding 25°C) and relative humidity (not exceeding 50%) were checked each day to maintain parity in experimental environment.
Height and weight were measured using standard laboratory equipment. The number of steps taken during walk was recorded by a pedometer. The step length was calculated based on height,[20] and the distance walked for the duration of 20 min was thus evaluated. Subsequently, the adopted speed was calculated. HGS of both hands for each participant was measured using a dynamometer (in kilogram units) before and after each walk. Standard procedure for handgrip measurement was followed; the subject was asked to stand and maintain an 180° forward shoulder flexion with full elbow extension (parallel to sagittal plane) since the handgrip is reported to be highest for this position.[21] Heart rate during walk was measured by Polar HR monitor. Pain occurrence during walk in the entire body was checked and noted.
Statistical analysis
All the variables considered in the study were checked for normal distribution. Since HGS was measured before and after walk, paired t-test was done, when different load carriage was considered, independent sample t-test was performed. Graphical and tabular form of data representation was done. Spearman's correlation was evaluated for nonnormal and categorical data. Phi correlation coefficient was evaluated if both the variables under consideration were dichotomous variables. Odd's ratio (OR) was evaluated to assess the association between the two variables.
| Results | | |
The alterations in HGS and pain perception due to the physical activity of schoolbag carriage was explored in participants belonging to the age group 10–15 years. The percentage change in HGS before and after walking with schoolbags was not found to differ significantly with age (P > 0.05). The characteristics of the study population have been represented in [Table 1]. All participants used their right hand dominantly and HGS of the dominant hand that is right hand was significantly greater than HGS of the left hand (paired t-test, P = 3.62E-10).
The participants were asked to walk at their preferred pace. The average speed adopted by the participants differed significantly (independent sample t-test, P = 0.001) while walking in no load and loaded conditions. The average speed adopted by the participants while walking for 20 min with no load was found to be 0.127 (±0.04) m/s while the average heart rate was 117 (±12) bpm or beats per minute. When carrying backpacks weighing 4%, 8%, 12%, or 16% of bodyweight, the average speed adopted by the participants was evaluated to be 0.157 (±0.04) m/s, the consequent average heart rate was 118 (±15) bpm. The adopted speed and the consequent average heart rate portrayed no significant association with HGS or percentage change in HGS.
HGS for each of the two hands as well as the HGS averaged for both hands was found to decrease after walking for 20 min either with or without a schoolbag [Figure 1]. This decrease was not significant when walking without schoolbag for 20 min (P > 0.05). During schoolbag carriage, only the HGS averaged for both hands decreased significantly after walking with schoolbag for 20 min (paired t-test, P = 0.033). | Figure 1: Change in Handgrip strength of the participants before and after walking
Click here to view |
The change in HGS before and after 20 min' walk was further analyzed by looking into this change for different weights of schoolbags carried. The means for the HGS of the left, right, and average of both hands have been represented in [Figure 2]; the differences seen were not significant (P > 0.05). | Figure 2: Change in Handgrip strength of the participants before and after walking for each load of schoolbags carried
Click here to view |
The percentage change in HGS for different loads of schoolbag carried was analyzed, given that HGS changed significantly after walking [Figure 3]. It was found that the percentage change in HGS (averaged for both hands) when walking with schoolbag weighing 12% load of bodyweight was significantly different compared to when walking with 4% and 8% load of bodyweight. Furthermore, the percentage change in HGS for right hand was different significantly for 8% and 12% load carriage. | Figure 3: Percentage change in Handgrip strength of the participants for each load of schoolbag carried (*P<0.05, significantly different)
Click here to view |
The percentage change in HGS was found to be higher when the load of schoolbag increased and this association was significant for right hand (dominant hand for all participants) [[Table 2], Spearman's rho = 0.20, P = 0.045]. Based on these results, the percentage change in HGS of right hand was dichotomized (0 – if there was no increase, 1 – if it increased after walk) and its association was sought with occurrence of pain (another dichotomous variable; 0 – no pain perceived, 1 – pain perceived) in the entire body. | Table 2: Association between load of schoolbag carried and percentage change in handgrip strength
Click here to view |
Pain was reported mainly in the neck, shoulder, and back regions for the 101 walks considered. Neck, back, and shoulder pain were reported 13.9%, 29.7%, and 35.6% of times, respectively. Occurrence of shoulder pain was positively associated with increase in percentage of load carried (Spearman's correlation = 0.61, P = 8.29E-12). The occurrence of shoulder pain was also found to be significantly associated to increase in HGS of right hand after walking as indicated by the Phi coefficient 0.21 (P = 0.030). This suggests that, if shoulder pain was perceived during walk, the participant would likely have a higher HGS in right hand after walk compared to before. This was further explored by evaluating the OR. The OR was found to be 2.515 (95% confidence interval, lower bound = 1.086, upper bound = 5.825), suggesting that if shoulder pain was perceived during walk, there was a 2.5 times higher likelihood that the participants' HGS for right hand increased.
| Discussion | | |
This study establishes the changes in HGS of children aged 10–15 years after performing the physical activity of schoolbag carriage for 20 min at their preferred pace with different load intensities. The average HGS obtained here 17.9 (±6.48) kg is comparable to previous report on Indian children.[22] Although age can be a factor affecting HGS,[23] this study evaluated that the percentage change in HGS before and after schoolbag carriage was not affected by age. The grip-strength of the dominant hand of the participants was significantly greater than the grip-strength of the nondominant hand. This conforms to previous studies that states dominant hand has higher grip strength than the nondominant hand.[24],[25]
The participants adopted higher speed while walking with backpacks, and correspondingly, there was a significant decrease in HGS averaged for both hands from 17.78 kg to 17.36 kg after walking with schoolbags for 20 min [Figure 1]. At higher walking speed, the average heart rate was also found to be higher. Higher intensity of physical activity at higher walking pace may be the cause behind this observation. Grip strength is known to decrease significantly from 28.41 kg to 26.75 kg and 25 kg due to moderate and high-intensity physical activity, respectively.[26]
HGS was found to decrease after walking for 20 min for 0%, 4%, 8%, and 16% load carriage but HGS increased after walk for 12% load carriage [Figure 2]. Carrying 10% load is reported to cause activation of the trapezius muscle.[27] Furthermore, higher trapezius muscle activation is associated with higher HGS.[28] This may be the reason behind the observation. This increase in HGS was not observed for 16% load carriage and may be due to the reason that the number of walks considered here are less (walks were terminated complying to research ethics if participants complained of increased pain). The decrease in HGS after 16% load carriage can also be attributed to fatigability due to carrying heavy load. Further exploration in a larger sample is needed to form conclusive delimitations.
While the HGS decreased after walk for 4% and 8% load carriage, it increased for 12% load carriage. This may be due to the fact that more physical activity increases muscle strength that is reflected in increased HGS.[29] Variation during 16% load carriage did not follow the trend but that may be due to reduction in the number of walks considered since many participants could not complete the walk (16.67%) due to perception of increased pain.
Pain in neck, shoulder, and back due to schoolbag carriage is most frequent.[30] Among the 101 walks considered here, neck, back, and shoulder pain were reported 13.9%, 29.7%, and 35.6% of times, respectively. The relationship of HGS with neck pain has been explored in dentists,[16] industrial workers;[14] with back pain has been explored in older women,[31] health-care workers.[9] Studies on the association of HGS and pain in children due to the schoolbag carriage are under-reported. Although this study did not find any significant association between HGS and neck/back pain among the participants, further explorations are needed inclusive of pain intensities to form definite conclusions.
Increase in HGS of right hand was found to be simultaneous with the occurrence of shoulder pain (Phi coefficient = 0.21, P = 0.030), conforming to prior reports.[15],[28] The same relationship had an OR of 2.515. The odds of having low HGS is reportedly higher among the individuals not performing aerobic physical activity (OR = 1.415).[32] The observation may be due to the reason that backpack carriage increases the activity in trapezius muscle,[27] stretching over in shoulder and neck region which may in-turn increase the HGS.
This pilot study explores the immediate consequences of schoolbag carriage on the HGS in children. This study can be further extrapolated to individuals involved in other forms of load carriage where HGS plays an important role like workers in brick manufacturing unit, tea gardens, and porters. The small sample size of the study is attributed to difficulty in co-operation since participation entailed presence for 5 consecutive days and the experimental procedure is elaborate. Exploration in a larger sample inclusive of pain intensities and not merely occurrence of it, besides conducting investigation in female sub-population can help generalize the results and will pave the path for future investigations.
| Conclusion | | |
The physical activity of schoolbag carriage significantly influences the HGS in children. Upper body conditioning exercises to improve strength are recommended to shield one from the ill effects of heavy schoolbag carriage.
Acknowledgment
The work was ethically approved by Institutional Ethical Committee (Human), Presidency University, Kolkata (PU/IEC(H)/CL/A01/2018). This work is part of a doctoral thesis to be submitted to Presidency University, Kolkata towards partial fulfilment of a PhD degree and we thank all the participants and their guardians for their kind consideration and support towards fulfilment of the study.
Financial support and sponsorship
The funding for this work was provided by Department of Science & Technology and Biotechnology, Government of West Bengal (WBDST) under grant 114(Sanc.)/ST/P/S& T/9G-3/2018 from 2018-2021.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]
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