Anthropometry of students
From Table 4, the 5th, 50th, 95th percentile values of stature (height) were 106.00, 119.00 and 133.00 cm. This shows that 95% of the population have a height below 133.00 cm and 95% of the population have a height above 106.00 cm. However, the 50th percentile value of stature is almost equivalent to the mean which explains that 50% of the participants have a standing height that is nearly same as the mean stature.
From Table 5, the results showed some socio-economic differences in anthropometric measurements of the school children. In this study, generally participants from relatively higher socioeconomic area schools had slightly greater body dimensions than those from relatively low socioeconomic area schools except for five variables. These five dimensions are; stature, popliteal height, sitting shoulder height, buttock-knee length and knee height. It has been reported in literature that socio-economic factor is a determinant for growth in children. Castellucci et al., (2010) established that children from higher socio-economical background are taller as compared to those from lower socio-economical background. However, in this study, children from lower socio-economical background were on average 0.19 cm taller than their counterparts from higher socio-economical background. During field work, it was observed that most of the students in the relatively low socioeconomic area schools were enrolled in school at a relatively advanced age than their counterparts in the relatively high socioeconomic area schools. Castellucci et al. (2014) stated that student growth differs with age and their legs also grow rapidly before puberty. This could have attributed to the observed trend in the standing height, popliteal height, buttock-knee length and knee height of the participants from lower socio-economic background. Moreover, not only were some of the children from the relatively low socioeconomic area schools overaged, they were not punctual to school.
Table 6 revealed observable differences in the measured anthropometric parameters of children from various classes. For example, the mean values of stature for class one, kindergarten two and one, are 125.34, 117.28, and 113.22 cm respectively. This finding is reinforced by (Yeats, 1997) who communicated that learners differ greatly in body dimensions, cross the different age groups and within the same age groups thus not all learners match their classroom seat and table. Moreover, this finding confirms the study by Panagiotopoulou et al., (2004) who conveyed that anthropometric measures can vary for school children in different classes as well as for those in the same class. The mean values of popliteal height for class one, kindergarten two and one, are 34.70, 32.08, and 30.32cm. This trend is line with the study by Bass et al., (1999) who conveyed that the legs grow faster than the trunk before adolescence and the growth of an individual is primarily truncal in adolescence. The results revealed that, in all measured body dimensions, the mean values of pupils in class one showed the largest body dimensions, followed by kindergarten two and one, except for hip width, thigh thickness and sitting elbow height. For these three dimensions, the largest body dimensions were observed in class one pupils followed by kindergarten one and two. Agha, (2010) conveyed that the body measurements of pupils increase with age which is in agreement with the findings of this study.
Table 7 presented the different measured body dimensions of boys and girls. The results suggest that there are no significant variations in the mean values of the measured anthropometrics for both sexes in this study. The mean standing height for males is 118.80 cm and 119.46 cm for girls. It is observed that the girls were on average 0.66 cm taller than the males. For both males and females, the mean popliteal height, hip width, sitting shoulder height and body weight were, correspondingly, 32.46 and 32.60 cm, 31.41 and 31.70cm, 39.29 and 39.59 cm, and 21.63 and 21.34 kg. This finding supports the study by Castellucci et al., (2015a) who conveyed that, in terms of gender differences, it can be seen that, boys and girls grow at comparable rate until puberty. They also found out that, with the exception of certain variables such as hip breadth, boys usually have larger body dimensions than girls after puberty.
Dimensions of students’ classroom furniture
From Table 8, it is noteworthy that the classroom furniture in all four schools differed in their dimensions. Communication with administrators of the various schools indicated that the furniture was procured without any considerations for the anthropometrics of the schoolchildren.
The compatibility between anthropometric indices of the children and furniture
The findings revealed a considerable level of discordancy between the measured furniture and the anthropometrics of the learners. This is due to the negligence of user anthropometry during the construction of educational furniture.
Table 9 presents the ergonomic suitability of the furniture for all participants. It gives the degree of match and incompatibilities for the furniture. For example, only 18.23% of the children had chair height that suited their popliteal height. Chair height was low for 54.18% of the children and too high for 27.59% of them. The seat depth was too deep for 80.51% of participants, only 15.19% had appropriate seat depth. The seat to desk height also revealed 25.06% match, 69.11% low mismatch and only 5.82% high mismatch. The match percentages of seat desk clearance, seat width and desk depth are 72.91%, 66.08% and 36.46% respectively.
Table 10 shows the match and mismatch percentages according to the socio-economic area of schools. The match percentages of seat height are 24.61% for low socio-economic area of schools and 12.25% for high socio-economic area of schools. The seat height was too low for 45.55% of children from low socio-economic area of schools and
62.25% of children from high socio-economic area of schools. The seat depth was too deep for 91.62% of children from low socio-economic area of schools and 70.10%of children from high socio-economic area of schools. Chair to table clearance presented the maximum match of at least 72% of children from both socio-economic backgrounds. Seat width was appropriate for at least 65% of participants from both socio-economic backgrounds.
Table 11 shows the match and mismatch percentages across all classes. The seat height fitted 21.74% of class one pupils, 21.05% of kindergarten two pupils and 12.23% of kindergarten one pupils. It was noteworthy that seat width suited 90.06% of class one pupils. Seat to desk clearance showed the highest degree of compatibility for the measured dimensions of furniture across all classes. The matched percentages were 84.47% of class one pupils, 62.11% of kindergarten two pupils and 66.91% of kindergarten one pupils.
Tables 12 and 13 presented the match and mismatch percentages by gender. The seat height matched only 15.82% of boys and 20.60% of girls. The seat width suited 66.84% of boys and 65.33% of girls. The seat desk clearance elicited matched percentages of at least 72% for both boys and girls. The desk depth was inappropriate for both majority of the children.
Health Implications of Incompatibility
The incompatibility between measured furniture dimensions and the anthropometry of the school children stimulates implications on health. Musculoskeletal disorders (MSDs) may occur in an educational setting as a result of continued flexion instigated by incompatibility between schoolchildren and their classroom furniture or heavyweight schoolbags. Children are vulnerable to musculoskeletal disorders because they remain seated on ill-fitted furniture in the classroom for long hours. Prolonged hours of sitting can result in the slow movement of the blood which may subsequently form clots within a vein and trigger deep venous thrombosis. Awkward sitting posture by students is a key negative effect of poorly designed furniture. Mismatched heights of chair and desk instigate poor body posture and pain which eventually interrupts learning. Murphy et al., (2007) argued that seats with very high backrests are associated with pain in the lower back. They reported that seats that are too low are associated with pain in the neck, upper back, and lower back. Unsuitable postures can result in repetitive strain injuries that affect tertiary students, teens, and pupils (Agha, 2010). Assuming unhealthy postures for deskbound activities such as scribbling, or reading can result in pain in the shoulders, neck, feet (Milanese & Grimmer, 2004; Osquei-Zadeh et al., 2012). Children will find it difficult to rest their feet correctly on the floor when seated on elevated chairs. It is established that a chair that suits learners with short legs can also accommodate learners with long legs (Mokdad & Al-Ansari, 2009). Seats with extreme heights cause compression of the underside of the thighs leading to awkwardness and improper movement of blood around the legs. Chairs with intense seats press firmly against the popliteal opposing supply of blood to parts of the thigh. High-swallowed seats affect the lower thigh and results in unsuitable sitting position. High table surfaces result in forward bending for deskbound tasks. Children are likely to experience kyphotic postures from chairs that are too deep.