In this study, it has been reviewed that recent developments like estimation of lower back loads and large-array surface electromyography (LA-SEMG) can be potent in low back pain estimation. Various approaches using biomechanical models had been used to estimate LBP. 

Low back pain (LBP) is the leading disabling musculoskeletal disorder globally making it a major public health problem. A number of biomechanical methods in which kinematic, kinetic and/or neuromuscular approaches are used to study LBP. In this narrative review, recent developments in two of such biomechanical methods: estimation of large-array surface electromyography (LA-SEMG) and lower back loads and the findings associated with LBP are reported. The estimation of lower back loads is very important for the management of work-related low back injuries and prevention, based on the mechanical loading model as one category of LBP classification.

The methods used for the estimation of lower back loads vary from simple rigid link-segment models to the sophisticated ones, optimization-based finite element models. In general, reports of differences in mechanical loads experienced in lower back tissues between patients with LBP and asymptomatic individuals were reviewed and were not consistent. The lack of consistency is primarily due to differences in activities under which the lower back mechanical loads, as well as heterogeneity of patient populations, were investigated. The ability to examine trunk neuromuscular behaviour is particularly relevant to the motor control model, another category of LBP classification. LA-SEMG not only is noninvasive but also provides spatial resolution within and across muscle groups. 

Studies using LA-SEMG showed that healthy individuals exhibit highly organized, symmetric back muscle activity patterns, suggesting an orderly recruitment of muscle fibres. In contrast, back muscle activity patterns in LBP patients are asymmetric or multifocal, suggesting a lack of orderly muscle recruitment. LA-SEMG was also found capable of capturing unique back muscle response to manual therapy.

The study concluded that the estimation of low back load and LA-SEMG techniques showed promising potentials for understanding LBP and strategic treatment effects. Future studies are warranted to fully establish the complete clinical validity of both biomechanical methods.