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Hand grip strength is a fundamental part of human factors and ergonomics. The main objective of the study was to predict Filipino teenagers’ hand grip strength by utilizing stepwise multiple linear regression. A total of 200 data were collected from Mapua Senior High School students. Stepwise multiple linear regression indicated that gender was found to have the most significant effect on the hand grip strength, followed by wrist circumference, arm circumference, and hand dominance. In addition, there was no significant difference between student grade 11 and 12. This study is the first study that explored the hand grip strength among Filipino teenagers and it would be very beneficial for human factor engineers, medical doctors, even hand therapists. Finally, the proposed stepwise multiple linear regression approach could be applied and extended in analyzing the hand grip strength in other countries.

In recent decades, issues of resource depletion and waste piling have grown at an alarming rate, which are happening in the cases of product wastes with significant residual values, such as e-waste. To address these issues, stakeholders have focused to develop a reverse supply chain (RSC) system that can sustain profitable takeback, reuse, and recycling operations in the long-term. Such a system requires efficiency in handling complex operations involving various players while being responsive to demand uncertainty and changes. One way in realizing these capabilities is by incorporating postponement concepts to the integrated RSC network, allowing the delay of operations susceptible to demand uncertainty. This study pioneers the formulation of a two-stage stochastic mixed-integer model of a multi-player RSC with speculation-postponement strategies. The sample average approximation method is used to solve and verify the proposed model that has an uncertain demand. Various speculation-postponement strategies, namely, disassembly, reconditioning, and reassembly strategies are developed to configure forecast and demand-driven RSC operations, including the purchasing, product takeback, production planning, inventory, and item speculation decisions. Numerical examples of the notebook computer RSC demonstrate that utilizing the right operation postponement can increase the network’s flexibility, allowing better economic performances even under high demand uncertainty risks and stricter environmental regulations. In various cases, the RSC performs better with speculation-postponement strategies than without postponement strategy, demonstrating the proposed model’s superiority. This study can provide insight to decision-makers to improve RSC sustainability through postponement. Moreover, the model is generic and can be applied to other products as well.

Hand grip strength, or widely also known as Maximum Voluntary Contraction (MVC), is an important part in physical ergonomics. The purpose of the study was to establish Filipino teenagers’ hand grip strength data. In addition, another objective of the study was to investigate the causal relationships of gender, hand anthropometric, hand dominance, and high school grade on hand grip strength in Filipino teenagers by utilizing the Structural Equation Modeling (SEM) approach. A total of 100 male and 100 female students were voluntary recruited from Mapua Senior High School students to perform MVC. SEM indicated that gender was found to have the most significant effect on the hand grip strength, followed by hand anthropometric, and hand dominance. Interestingly, hand dominance was found to be significant on hand grip strength. This study is the first study that establish the hand grip strength among Filipino teenagers and it would be very beneficial for human factor engineers, hand therapists, and even medical doctors. Finally, the proposed SEM approach could be applied and extended in analyzing the hand grip strength in other countries.