Comparison of foot posture and foot muscle morphology between lifesaver athletes and healthy adults

Functional relationship between the foot intrinsic and extrinsic muscles in walking

The intrinsic and extrinsic muscles are considered to stabilize the foot and contribute to propulsion during walking. This study aimed to clarify the functional relationship between intrinsic and extrinsic muscles during walking. Thirteen healthy men participated in this study. The muscle activities of the intrinsic muscles (quadratus plantae and abductor hallucis), and the extrinsic muscles (flexor hallucis longus, flexor digitorum longus, and tibialis posterior) were measured using fine-wire and surface electromyography during walking. The muscle onset timing after foot contact was calculated and compared among muscles using the one-way ANOVA. The stance phase was divided into early and late braking, and early and late propulsion phases. Muscle activity among phases was compared using repeated-measures ANOVA. The onset time of the abductor hallucis was significantly earlier than those of the flexor digitorum longus and tibialis posterior. The quadratus plantae demonstrated significantly earlier onset than that of the tibialis posterior. In the late propulsion phase, the activity of extrinsic muscles decreased, whereas intrinsic muscles were continuously active. Early activation of the intrinsic muscles may stabilize the foot for efficient torque production by the extrinsic muscles. Furthermore, the intrinsic muscles may contribute to the final push-off after the deactivation of extrinsic muscles.

Effect of exercise training on arterial stiffness in obese and overweight children: a meta-analysis

The aim of this study was to investigate the effect of exercise training on arterial stiffness in obese and overweight children. Three databases were searched up to July 2021 for papers about exercise training and arterial stiffness in obese and overweight children. The quality of each identified study was evaluated. Effect sizes were estimated in terms of the standardized mean difference. Egger's test and sensitivity analysis were used to assess publication bias. In total, 26 studies by 19 researchers were included in the meta-analysis. Flow-mediated dilatation (FMD), pulse wave velocity (PWV), and intima-media thickness (IMT) were improved after exercise training in obese and overweight children. Subgroup analysis showed that exercise only reduced the PWV and IMT in individuals with a BMI < 30. FMD, PWV, and IMT were improved by exercise training in participants aged below 14 years, but only FMD was increased by exercise in participants aged 14 years and above. All types of training significantly improved FMD. Aerobic exercise (AE) and high-intensity intermittent training (HIIT) reduced the PWV of the participants, but were less effective than resistance training (RT) and aerobic plus resistance training. Only HIIT significantly reduced the IMT.   Conclusions: Exercise training improved vascular endothelial function and vascular sclerosis in overweight and obese children, especially in those with a BMI < 30 and younger than 14 years. AE had a more favorable effect on arterial stiffness. What is Known: • Exercise training was a good way to lose weight and subsequently promoted vascular function in overweight and obese children. What is New: • Exercise training was more effective on the vascular endothelial function and vascular sclerosis in overweight and obese children with a BMI<30. • Aerobic exercise had a more favorable effect on arterial stiffness, while the improvement was not effective after resistance training and combined training mode.