Immediate characteristics of acupuncture have been confirmed by relevant studies; however, the current study on the time effect of acupuncture in improving upper limb forearm muscle endurance is still limited. The aims of this study are to explore: (1) whether real acupuncture (RA) can improve female forearm muscle endurance compared to sham acupuncture (SA) and (2) whether the changes in forearm muscle endurance after RA are time-dependent. Thirty-six healthy female students were recruited to participate in isokinetic tests of elbow flexion/extension (Flex/Ext) from maximum flexion to maximum extension as much as possible using an isokinetic dynamometer at a speed rate of 60°/sec. Participants in the RA group were stimulated at Quchi (LI11), Shousanli (LI10), Hegu (LI4), Xiaohai (SI8), Tianjing (SJ10), and Waiguan (SJ5) acupoints for 20 min, while the SA group needling was near at these acupoints. The values of the isokinetic parameters and surface electromyography (sEMG) signals were recorded before and after acupuncture. After RA, the isokinetic parameters values (average torque, work, power, and speed), the sEMG values at four major muscles, and the joint stiffness of elbow Flex/Ext were significantly increased $\left(p<0.05\right)$ . The enhancement of forearm muscle endurance lasted approximately 7–21 min (from post1 to post3/post4), indicating that the effect of RA to improve elbow Flex/Ext muscle endurance is time-dependent. Therefore, this study found that RA can immediately improve the forearm muscle endurance of healthy women compared with SA, and this effect can last approximately 7–21 min until the acupuncture efficacy decreased or disappeared.

Background: In the postpandemic era, wearing protective masks in public places will still be an important means of blocking popular viruses in the future. The purpose of this study was to explore whether sports performance was affected by mask wearing and exercise duration during 15-min treadmill running at a speed of 75% maximal aerobic speed. Methods: Thirty-six males were randomly divided into mask and nonmask groups. The kinematic and kinetic data were obtained at four time points (RN_0–1 min, RN_5–6 min, RN_9–10 min, and RN_14–15 min) during running. Two-way mixed ANOVA was applied to examine the effects between groups and times with Bonferroni post hoc comparison and independent samples t-test. Results: The results showed that there was no difference between mask and nonmask group during running (p > 0.05). As running time increased, hip joint ROM, hip joint flexion/extension max, and ankle joint plantarflexion max angles increased; knee joint flexion min and ankle joint dorsiflexion max angles decreased; average peak vertical ground reaction forces (PVGRF) increased after 9 min-running (p < 0.05). Conclusions: Wearing a medical protective mask does not affect the joint angle and touchdown PVGRF of lower extremities during treadmill running while affected by running time and changed after 9 min-treadmill running. Future studies will examine the effects of wearing masks during the pandemic on muscle activation and blood biochemical values during exercise. Trial registration No. ChiCTR2000040535 (date of registration on December 1, 2020). Prospectively registered in the Chinese Clinical Trial Registry.