Effects of load carriage and work boots on lower limb kinematics of industrial workers

Changes in Baropodometric Evaluation and Discomfort during the Workday in Assembly-Line Workers

Prolonged standing at work is associated with health risks. The appearance of lower-limb and lower-back discomfort is one of the most prevalent factors in prolonged standing workers. The aim of this research was to evaluate the effect of an eight-hour workday on foot pressure and musculoskeletal discomfort in standing workers. Thirty-six assembly-line workers (six women) were recruited to participate in a cross-sectional study to assess foot pressure and surface, foot, knee, and lower-back discomfort before and after a real workday. Baropodometry outcomes (surface and pressure) were evaluated by the pressure platform SensorMedica and musculoskeletal discomfort was evaluated by Cornell's Musculoskeletal Discomfort Questionaire. Total foot surface (p = 0.01) and foot discomfort (p = 0.03) increased significantly at the end of the workday. Prolonged standing during 8 h workday increased the foot discomfort and total foot surface in assembly-line workers. No foot pressure variable (forefoot, rearfoot, or total) was significantly modified after the workday in assembly-line workers.

Kinematic Strategies for Sustainable Well-Being in Aging Adults Influenced by Footwear and Ground Surface

Falls are an inescapable problem influencing the health and threatening the safety of older adults. Exploring the kinematic strategies of aging adults can help reduce the risk of falls. To study kinematic strategies of aging adults in response to footwear (flat shoes, toe spring shoes, rocker sole shoes) and ground surfaces (level ground, grassland and rock road), a 3D motion capture system and subjective stability evaluation, with 14 female participants, were performed. Results indicated that footwear and ground surfaces significantly impacted joint dynamics during walking. Compared with young adults, aging adults tended to adopt a more conservative walking pattern. Wearing different shoes on the three ground surfaces mainly reduced the ROM (range of motion) of the ankle (p < 0.05). By analyzing the objective and subjective results, rocker sole shoes gave aging adults a stronger sense of instability, so they controlled the movement of ankle joint initiatively. When walking on grassland and rock road, aging adults adjusted the movements of hip, knee and ankle joints to maintain gait stability. Aging adults are recommended to strengthen flexibility training of the ankle joint, perform hip adduction and abduction exercises, and wear rocker sole shoes to improve their balance ability and sustainable well-being.

6DOF knee kinematic alterations due to increased load levels

Whether load carriage leads to six-degrees-of-freedom (6DOF) knee kinematic alterations remains unclear. Exploring this mechanism may reveal meaningful knee kinematic information that can be used to improve load carriage conditions, the design of protective devices, and the knowledge of the effects of load carriage on knees. We recruited 44 subjects to explore kinematic alterations from an unloaded state to 60% bodyweight (BW) load carriage. A three-dimensional gait analysis system was used to collect the knee kinematic data. One-way repeated analysis of variance (ANOVA) was used to explore the effects of load levels on knee kinematics. The effects of increasing load levels on knee kinematics were smooth with decreased or increased trends. We found that knees significantly exhibited increased lateral tibial translation (up to 1.2 mm), knee flexion angle (up to 1.4°), internal tibial rotation (up to 1.3°), and tibial proximal translation (up to 1.0 mm) when they went from an unloaded state to 60%BW load carriage during the stance phase (p < 0.05). Significant small knee adduction/abduction angle and posterior tibial translation alterations (<1°/mm) were also identified (p < 0.05). Load carriage can cause significant 6DOF knee kinematic alterations. The results showed that knee kinematic environments are challenging during increased load. Our results contain kinematic information that could be helpful for knee-protection-related activities, such as target muscle training to reduce abnormal knee kinematics and knee brace design.

Effects of personal protective clothing on firefighters' gait analyzed using 3D motion capture system

OBJECTIVES

The effects of personal protective clothing (PPC) on firefighters' gait were investigated to develop high-performance PPC.

METHODS

Thirteen participants participated in human trials with three types of PPC (firefighter protective clothing (FPC); semi-enclosed chemical protective clothing (CPC_semi); full-enclosed chemical protective clothing (CPC_full)) and T-shirt (CON). A 3D motion capture system was used to obtain gait parameters (step length, step width, stride frequency, gait speed, and toe-out angle) and the range of motion (ROM) of the joints (hip, knee, and ankle).

RESULTS

PPCs produced an increase in step width (23.4%, p > 0.05), but the gait speed (9.1%) and stride frequency (6.4%) decreased compared with the CON results. ROM is affected by the PPC type and joint. FPC and CPC_semi had no significant effect in terms of the ROM of the hip and knee besides the landing angle of the knee. However, CPC_full had a significant effect on the maximum extension angle of the hip and maximum flexion angle of the knee, which reached up to 27.2%.

CONCLUSION

The ROM of the firefighter's lower limbs were limited by PPC. This study offers insights into next-generation PPC design and development, as well as guidelines for training and firefighting.