Original Research
Occupational Health

Analysis on the Effect of Personalised Insole for Prolonged Standing Industrial Workers

Background

Prolonged standing is one of the most common occupational demands faced by industrial workers worldwide. In Malaysia, millions of manufacturing and factory workers spend eight or more hours per day on their feet, often on hard concrete or metal flooring surfaces. This sustained postural loading places enormous biomechanical stress on the musculoskeletal system, particularly affecting the feet, ankles, knees, and lower back. Research has consistently demonstrated that workers who stand for extended periods face elevated risks of plantar fasciitis, chronic lower back pain, varicose veins, leg swelling, and general musculoskeletal fatigue.

The footwear provided to industrial workers, primarily safety shoes mandated under the Malaysian Occupational Safety and Health Act 1994, is typically designed with external hazard protection as the principal concern. These shoes incorporate steel toe caps, puncture-resistant soles, and slip-resistant outsoles, but the internal comfort and ergonomic support features are frequently inadequate. The factory-standard insoles inside safety shoes tend to be flat, thin, and made from low-cost materials that offer minimal cushioning or arch support. Over the course of a full work shift, this lack of personalised fit leads to uneven pressure distribution beneath the foot, concentrated loading at the heel and forefoot, and progressive discomfort that compounds into chronic musculoskeletal disorders.

Personalised insoles represent a targeted ergonomic intervention designed to address these issues. Unlike generic flat insoles, personalised insoles are custom-fitted or semi-custom-fitted to the individual worker’s foot morphology, providing tailored arch support, pressure redistribution, and shock absorption. The scientific rationale rests on the principle that an insole contoured to match the plantar surface of an individual’s foot will distribute body weight more evenly across a larger contact area, thereby reducing peak pressures at vulnerable anatomical points such as the metatarsal heads and calcaneus.

Study Design and Methodology

This study was conducted among industrial workers in a Malaysian manufacturing facility to evaluate the effects of personalised insoles on foot pressure distribution, comfort, and musculoskeletal symptoms during prolonged standing work. The research employed an experimental design comparing personalised insoles against the standard insoles provided with factory-issued safety shoes.

Participants were recruited from among workers whose job demands required standing for at least six hours per working day. Foot pressure measurements were obtained using an F-Scan in-shoe pressure measurement system, which captures dynamic plantar pressure data including peak pressure, mean pressure, and contact area across different foot regions. The foot was divided into anatomical zones comprising the heel, midfoot, forefoot, and toes for regional analysis of pressure distribution.

The personalised insoles were designed based on individual foot pressure mapping and anthropometric measurements. The insole material composition typically combined a firmer base layer for structural support with a softer upper layer for cushioning. Materials evaluated included ethylene vinyl acetate (EVA), polyurethane (PU), and poron, which is a microcellular urethane known for its excellent shock-absorbing properties. Workers wore each insole condition for a standardised period during their regular work shifts, and measurements were taken at multiple time points to capture the temporal progression of discomfort and pressure changes.

Key Results

The findings demonstrated that personalised insoles produced statistically significant improvements in plantar pressure distribution compared to standard factory insoles. Peak pressures under the heel and forefoot were notably reduced, with the personalised insoles redistributing load more evenly across the midfoot region. This shift in pressure distribution is biomechanically significant because it reduces the concentrated forces at anatomical structures most vulnerable to overuse injury, including the plantar fascia and metatarsal heads.

The combination of PU and poron emerged as a particularly effective insole material composition. Surface electromyography (sEMG) analysis of the gastrocnemius muscles showed significant differences in muscle activity between insole conditions, suggesting that the personalised insoles reduced the muscular effort required to maintain standing posture. This reduced muscle activation translates to slower onset of fatigue and lower risk of chronic muscle strain over extended work periods.

Subjective comfort assessments corroborated the objective pressure data. Workers reported meaningful reductions in foot pain, lower back discomfort, and general fatigue when using personalised insoles. These subjective improvements were most pronounced during the latter half of work shifts, when cumulative standing fatigue typically reaches its peak.

Implications for Occupational Health in Malaysia

These findings carry substantial implications for occupational health policy and practice in Malaysia’s industrial sector. The Malaysian manufacturing industry employs millions of workers, many of whom stand for prolonged periods under conditions that place them at elevated risk for musculoskeletal disorders. Current occupational safety regulations under DOSH (Department of Occupational Safety and Health) focus primarily on external hazard protection through mandated safety footwear, but the internal ergonomic quality of this footwear receives comparatively little regulatory attention.

The economic case for personalised insole interventions is compelling when considered against the costs of musculoskeletal disorder-related absenteeism, medical treatment, and reduced productivity. Musculoskeletal disorders are among the leading causes of work disability in Malaysia, and lower limb and back problems attributable to prolonged standing represent a significant proportion of these cases. A relatively modest investment in personalised insole programmes could yield meaningful returns through reduced sick leave, improved worker satisfaction, and decreased long-term healthcare expenditures.

International evidence supports the broader applicability of these findings. Studies in European and North American occupational settings have consistently shown that ergonomic insole interventions reduce plantar pressure, decrease musculoskeletal discomfort, and improve worker well-being. The Malaysian context, with its tropical climate adding heat and humidity challenges to prolonged standing, may present an even stronger case for personalised insole solutions that incorporate breathability and moisture management alongside biomechanical support.

Limitations

Several limitations should be considered when interpreting these results. The study was conducted at a single industrial facility, which may limit the generalisability of findings to other manufacturing environments with different flooring surfaces, standing durations, and worker demographics. The sample size, while adequate for detecting statistically significant pressure differences, may not capture the full range of individual variation in foot morphology and biomechanical response to insole interventions.

The follow-up duration was relatively short, and the long-term durability of both the insoles and the observed comfort benefits requires further investigation. Insole materials undergo compression and degradation over time, and the rate at which personalised insoles lose their customised contour and cushioning properties under industrial use conditions is an important practical consideration. Future research should evaluate the effectiveness of personalised insole programmes over extended periods of six months to one year, with attention to replacement intervals and cost-effectiveness over the insole lifecycle.

Additionally, the study focused primarily on biomechanical and comfort outcomes. Future research could benefit from incorporating clinical outcome measures such as rates of plantar fasciitis, lower back pain episodes, and healthcare utilisation among workers using personalised versus standard insoles over longer observation periods.

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