Wearing a Surgical Face Mask Has Minimal Effect on Performance and Physiological Measures during High-Intensity Exercise in Youth Ice-Hockey Players: A Randomized Cross-Over Trial.

COVID-19 transmission is prevalent during ice-hockey; however, it is unknown whether wearing face masks as a mitigation strategy affects hockey players' performance. We used a randomized cross-over study to compare wearing a surgical mask to a sham mask (control) in youth hockey players (21 males, 5 females, 11.7 ± 1.6 y) during a simulated hockey period (cycle ergometry; six shifts of 20 s of "easy" pedaling (40% peak power), 10 s of "hard" pedaling (95% peak power), 20 s of "easy" pedaling, with shifts separated by 5 min rests). A seventh shift involved two 20 s Wingate tests separated by 40 s rest. Heart rate, arterial oxygen saturation and vastus lateralis tissue oxygenation index (hemoglobin saturation/desaturation) was assessed each shift. On-ice testing was conducted with the maximal Yo-Yo intermittent recovery test. No differences between mask and control conditions for performance were found (Wingate average power: 245 ± 93 vs. 237 ± 93 W, Peak power: 314 ± 116 vs. 304 ± 115 W, on-ice distance: 274 ± 116 vs. 274 ± 110 m) and for heart rate or arterial oxygen saturation during simulated hockey shifts. Tissue oxygenation index was lower from shifts one to six for males (p < 0.05) and shift seven for females (p < 0.01) while wearing a mask. Wearing a face mask had no effect on performance in hockey players with only minor effects on muscle oxygenation. ClinicalTrials.gov (NCT04874766) (accessed on 6 May 2021).

The impact of face masks on performance and physiological outcomes during exercise: a systematic review and meta-analysis.

Face masks are promoted for preventing spread of viruses; however, wearing a mask during exercise might increase CO2 rebreathing, decrease arterial oxygenation, and decrease exercise performance. A systematic review and meta-analysis was conducted on the impact of wearing a mask during exercise. Data sources included SPORTDiscus, PubMed, and Medline. Eligibility criteria included all study designs comparing surgical, N95, or cloth masks to a no mask condition during any type of exercise where exercise performance and/or physiological parameters were evaluated. Healthy and clinical participants were included. Mean differences (MD) or standardized mean differences (SMD) with 95% confidence intervals were calculated and pooled effects assessed. Twenty-two studies involving 1573 participants (620 females, 953 males) were included. Surgical, or N95 masks did not impact exercise performance (SMD -0.05 [-0.16, 0.07] and -0.16 [-0.54, 0.22], respectively) but increased ratings of perceived exertion (SMD 0.33 [0.09, 0.58] and 0.61 [0.23, 0.99]) and dyspnea (SMD 0.6 [0.3, 0.9] for all masks). End-tidal CO2 (MD 3.3 [1.0, 5.6] and 3.7 [3.0, 4.4] mm Hg), and heart rate (MD 2 [0,4] beats/min with N95 masks) slightly increased. Face masks can be worn during exercise with no influences on performance and minimal impacts on physiological variables. PROSPERO registration: CRD42020224988. Novelty: Face masks can be worn during exercise with no impacts on performance and minimal impacts on physiological variables.

Investigation of supraspinatus muscle architecture following concentric and eccentric training.

OBJECTIVES: To investigate the effects of concentric or eccentric abduction strength training on supraspinatus fiber bundle architecture and strength. DESIGN: A pre-post single-subject design. METHODS: Thirteen participants were randomized to concentric (n=6) or eccentric (n=7) training groups. Participants completed an eight week shoulder abduction training program in the scapular plane using an isokinetic dynamometer. Resistance training, requiring maximal effort on contraction, consisted of 4 sets of 8 reps at 60°/s in weeks 1-4, and 6 sets of 6 reps at 60°/s in weeks 5-8 with a frequency of 3×/week. Primary outcome measures included fiber bundle length, pennation angle, and muscle thickness of supraspinatus and these were quantified using ultrasound. Secondary outcome measures included isometric, eccentric and concentric abduction strength and these were evaluated using the isokinetic dynamometer. RESULTS: Mean fiber bundle length in the relaxed (p=0.033) and contracted (p=0.036) states significantly decreased with concentric training but remained unchanged with eccentric training. A significant increase in pennation angle, muscle thickness, and peak torque were found with training but no significant differences were detected between concentric and eccentric groups. CONCLUSIONS: Training mode has a significant impact on fiber bundle length changes of the supraspinatus. Eccentric training of shoulder abduction leads to similar strength gains as concentric, but it may also have the added advantages of maintaining fiber bundle lengths and promoting tendon healing. Study is needed to confirm fiber bundle changes in a clinical population which would further support the use of eccentric abduction strength training in rehabilitation settings.

The structure of NtdA, a sugar aminotransferase involved in the kanosamine biosynthetic pathway in Bacillus subtilis, reveals a new subclass of aminotransferases.

NtdA from Bacillus subtilis is a sugar aminotransferase that catalyzes the pyridoxal phosphate-dependent equatorial transamination of 3-oxo-α-D-glucose 6-phosphate to form α-D-kanosamine 6-phosphate. The crystal structure of NtdA shows that NtdA shares the common aspartate aminotransferase fold (Type 1) with residues from both monomers forming the active site. The crystal structures of NtdA alone, co-crystallized with the product α-D-kanosamine 6-phosphate, and incubated with the amine donor glutamate reveal three key structures in the mechanistic pathway of NtdA. The structure of NtdA alone reveals the internal aldimine form of NtdA with the cofactor pyridoxal phosphate covalently attached to Lys-247. The addition of glutamate results in formation of pyridoxamine phosphate. Co-crystallization with kanosamine 6-phosphate results in the formation of the external aldimine. Only α-D-kanosamine 6-phosphate is observed in the active site of NtdA, not the ß-anomer. A comparison of the structure and sequence of NtdA with other sugar aminotransferases enables us to propose that the VIß family of aminotransferases should be divided into subfamilies based on the catalytic lysine motif.