This study investigates the effects of low-intensity high-repetition (LI-HR) and high-intensity low-repetition (HI-LR) resistance training (RT) on functional fitness and myokines in older adults. A total of 30 participants (mean age ~76 years) were randomized into control (n = 10), LI-HR (n = 10), or HI-LR (n = 10) groups. Participants in LI-HR and HI-LR groups performed elastic band-based RT three times per week for 12 weeks. Pre- and post-intervention assessments included functional fitness (relative grip strength, sit-to-stand, 4 m walk, timed up-and-go (TUG)), ankle muscle strength, lower extremity power, and myokine levels (IL-6, IGF-1, SPARC, BDNF). Both experimental groups showed significant IL-6 reduction (LI-HR: p = 0.033; HI-LR: p = 0.015) and IGF-1 increase (LI-HR: p = 0.003; HI-LR: p < 0.001). SPARC increased significantly only in the HI-LR group (p = 0.021). Functional improvements were noted in TUG for both groups, while the 4 m walk improved significantly in the HI-LR group (p < 0.001). Body fat percentage increased in both LI-HR (p = 0.003) and HI-LR (p = 0.047). In conclusion, both LI-HR and HI-LR RT effectively enhance functional fitness and key myokines, with LI-HR emerging as a promising, accessible option for older adults.

Advanced glycation end-products (AGEs) contribute to metabolic dysfunction and sarcopenia by promoting oxidative stress and inflammation. The therapeutic impact of exercise on AGEs-induced muscle deterioration and clinical relevance of skin autofluorescence (SAF) as a biomarker remain unclear. Therefore, we aimed to comprehensively investigate the physiological effects of AGEs using two complementary approaches. This study comprised an animal experiment and a human observational study. In Experiment 1, male mice were administered methylglyoxal (MGO) to induce muscle atrophy and treated with or without treadmill exercise for 12 weeks. Muscle morphology, function, and atrophy-related markers were evaluated. In Experiment 2, 37 older adults (≥65 years) were stratified into low-SAF (2.7 AU) groups. Nε-(carboxymethyl)lysine (CML) and secreted protein acidic and rich in cysteine (SPARC) levels were compared. In mice, muscle atrophy induced by MGO was associated with upregulation of MuRF1 and Atrogin-1, increased fibrosis, and suppression of MyoD and myogenin proteins. Aerobic exercise prevented these effects, restoring muscle mass, enhancing glucose transporter type 4 and myosin heavy chain expression, and reducing SMAD2/3 signaling. In humans, the high-SAF group showed elevated insulin resistance, higher CML, reduced SPARC, and poor performance in grip strength, five times sit-to-stand (STS), 2-min walk test, and STS power. SAF positively correlated with CML and negatively with muscle function. Aerobic exercise mitigates AGEs-induced muscle deterioration through molecular and structural improvements. SAF and CML may serve as noninvasive biomarkers of functional decline in older adults. These findings highlight the potential of exercise to counteract sarcopenia associated with AGEs accumulation.

Background/Objectives: Advanced Glycation End Products (AGEs) are high-molecular-weight compounds formed through non-enzymatic reactions between sugars and proteins, lipids, or nucleic acids. This study aimed to comprehensively analyze the association between the accumulation of AGEs and lower-limb muscle strength, gait speed, and balance abilities related to mobility in elderly individuals. Methods: This cross-sectional correlational study included 552 community-dwelling older adults. AGE accumulation was assessed using skin autofluorescence (SAF) measured using an AGE reader. Mobility decline factors were evaluated using the sit-to-stand (STS), gait speed (4 m walk tests), single-leg stance (SLS), and Timed Up and Go (TUG) tests. Results: A comparison of the physical function across the quartile groups revealed that the group with the highest SAF values, Q4, exhibited a general decline in STS, gait speed, SLS, and TUG performance when compared with the other groups (p < 0.001). Spearman’s correlation analysis revealed that the SAF-AGEs demonstrated significant negative correlations with STS (r = −0.211, p < 0.001), gait speed (r = −0.243, p < 0.001) and SLS (r = −0.201, p < 0.001). Additionally, TUG showed a significant positive correlation (r = 0.239, p < 0.001). In the logistic regression analysis, compared with the Q1 group, the Q4 group had significantly higher odds of low STS performance (odds ratio (OR) = 2.43, p = 0.006), slow gait speed (OR = 2.28, p = 0.002), low SLS performance (OR = 2.52, p = 0.001), and slow TUG (OR = 2.00, p = 0.035). The optimal cutoff value of the SAF for mobility decline was 3.15 (area under the curve 0.694; 95% confidence interval: 0.618–0.771). Conclusions: This study has demonstrated that higher SAF values were associated with decreased lower-limb strength, gait speed, and balance, thereby suggesting that SAF may be a useful screening tool for predicting mobility decline in older adults.

This cross-sectional study aimed to identify the interactions between lifestyle-related, diagnostic, and physical strength-related sarcopenia factors. The study included 512 female participants aged 60–100 years from Incheon, Republic of Korea, recruited from 12 institutions. Participants engaged in the study from June to August 2023. We administered questionnaires on demographic characteristics and health indicators and undertook physical measurements, including grip strength and body composition. Hierarchical regression analysis and two-way analysis of variance were conducted to examine the association between sarcopenia and the examined variables. Statistical significance was set at p < 0.05. Hierarchical regression analysis of the variables affecting sarcopenia showed each characteristic’s effect: Model 1 (basic characteristic): R², 0.391; p < 0.001; Model 2 (Model 1 + additional characteristics): R², 0.427; p < 0.001. Hierarchical regression analysis of diagnostic and fitness factors affecting sarcopenia also showed an effect on sarcopenia (Model 1 (basic characteristics): R², 0.318; p < 0.001; Model 2 (Model 1 + body composition): R², 0.419; p < 0.001; Model 3 (Model 2 + fitness factors): R², 0.664; p < 0.001). This study enhances the understanding of sarcopenia by investigating its connections with sociodemographic factors, lifestyle choices, and physical activity. The study underscores that lifestyle factors sustainably influence sarcopenia while confirming its correlation with fitness-related factors. Notably, this study highlights the results that muscle function is very important in preventing sarcopenia and that continuous physical activity and types of physical activity affect it.

[Purpose] This case report evaluates changes in body composition, physical fitness, and quality of life in a patient with Guillain-Barre syndrome (GBS) undergoing training with an end-effector gait robotic device.[Methods] A 35-year-old man with GBS completed interval training using a robotic gait assistant three times weekly for four weeks. The training intensity was set at 70–75% (Phase 1) and 80–85% (Phase 2) of the target heart rate, calculated using the heart rate reserve. Evaluations included body composition, physical fitness, isometric strength, gait performance, and quality of life indices.[Results] Post-intervention, improvements were observed across all parameters. Body weight increased by 1.2%, while body fat percentage and visceral fat decreased by 5.4% and 3.7%, respectively. Muscle mass increased by 3.3%, and isometric strength improved at all tested sites. Gait speed increased from 0.7 to 1.8 km/h (157.1%), and the number of steps per minute increased from 33 to 77 (133.3%). The timed up-and-go (TUG) test improved by 7.1%, and exercise self-efficacy (ESE) scores increased by 29.1%.[Conclusion] These findings align with the principles of neuromuscular adaptation, motor learning, and neuroplasticity. Interval training with a robotic gait device may effectively restore physical function and improve quality of life in patients with GBS. However, the limitations of this single case study highlight the need for randomized controlled trials with larger cohorts and long-term effectiveness assessments.