Food Science of Animal Resources (Food Sci. Anim. Resour.) is an international, peer-reviewed bimonthly journal publishing original research and reviews on basic and applied aspects of the use of animal resources including the meat, egg, dairy, and edible insect/worm products. Food Sci. Anim. Resour. is published and distributed by the Korean Society for Food Science of Animal Resources.

Ki Hong Kim, Byung Kwan Kim. Medical Lasers; Engineering, Basic Research, and Clinical Application 2021;10:153-60. https://doi.org/10.25289/ML.2021.10.3.153

Hwan Jong Jeong, Byung Kwan Kim, Gi Seon Yoo, Ki Hong Kim. Med Lasers 2023;12:108-15. https://doi.org/10.25289/ML.22.008

This study investigated the associations among age, physical activity level, knee muscle function, and neuromuscular junction (NMJ) biomarkers in a cohort of 80 middle-aged and young men residing in the Republic of Korea. Despite comparable levels of physical activity between the groups, the middle-aged participants exhibited significantly higher body fat percentage, elevated levels of the neurodegeneration marker neurofilament light chain (NfL), and a marked decline in lower-extremity muscle function compared to their younger counterparts. Advancing age was negatively associated with knee extensor peak torque, body weight–normalized torque (BW/PT), and the rate of torque development at 0.18 s (RTD@0.18s). In contrast, higher physical activity levels were positively correlated with certain indicators of muscle function and were associated with lower circulating concentrations of the NMJ degeneration marker, C-terminal agrin fragment (CAF). These findings suggest that neuromuscular decline and muscle function deterioration may begin as early as middle age. The results underscore the importance of implementing tailored exercise regimens and lifestyle interventions to preserve neuromuscular health and prevent early-onset muscle loss.

Jason Kang, Ki Hong Kim, Byung Kwan Kim. Med Lasers 2025;14:110-8. https://doi.org/10.25289/ML.25.013

Rapid torque production may reveal age-group differences not captured by peak torque. This exploratory cross-sectional study included 83 men in their 20s (n = 20), 30s (n = 21), 40s (n = 22), and 50s (n = 20). Knee-extension torque at 180°/s was recorded 50, 100, 200, and 300 ms after onset and at peak. Interval-specific torque change, vastus medialis electromyography, Lower Quarter Y-Balance Test performance, serum C-terminal agrin fragment (CAF) and neurofilament light chain (NfL) were assessed. Absolute and body-weight-normalized torque differed at every fixed time and at peak (all p < 0.001). At 300 ms, absolute torque separated the 20s group from all older groups and the 30s and 40s groups from the 50s group; peak torque separated only the 20s group from older groups. Torque-change and EMG-amplitude differences were phase dependent. Y-Balance scores were lower in the 50s group than in the 20s and 30s groups. CAF was higher in the 40s group than in the 20s and 30s groups. NfL was excluded from quantitative group comparisons because 48 of 83 results (57.8%) were below the laboratory-reported lower limit of quantification (9.38 pg/mL). Fixed-time torque may complement peak torque, but the design and exploratory multiple testing preclude causal or longitudinal inference.