Self-powered triboelectric wearable biosensor using Scotch tape.

A novel self-powered wearable triboelectric biosensor concept is proposed in this paper, which consists of Scotch tape and a metalized polyester sheet (Al/PET). The Scotch tape is the sensing element by exploring the interaction between the tape polypropylene backing material and the acrylic adhesive layer when pressing and releasing. The polypropylene surface only has partial positive charges because of a nonpolar surface, while the acrylic adhesive has a polar surface with positively and negatively charged and neutral regions. Atomic size gaps are formed because of the attractive and repulsive areas at the interface due to van der Waals forces. These density depleted regions act as 'geometric' gaps to produce triboelectric charges via contact and separation on a microscopic scale. This leads to our wearable biosensor design for measuring human body motion. Associated skin contraction and relaxation during body motion will activate the contact and separation between the polypropylene and acrylic adhesive layer when the sensor assembly is adhered to the skin. Various demonstrations were conducted to detect different body motions, including elbow flexion at a low angle, forearm protonation, forearm supination, knee flexion/extension, proximal interphalangeal flexion/extension, temple motion due to eye blinking, and temporomandibular opening. Unique features can be identified which are associated with different body motions. Moreover, the measurements from our triboelectric sensor correlate well with the results from a commercial electromyography (EMG) sensor in an isokinetic leg extension test, which leads to a new method of measuring human muscle activation.

Acute Effects of Facial Coverings on Anaerobic Exercise Performance in College-Aged Adults.

The use of facial coverings has been amplified during the COVID-19 pandemic as a means to minimize the spread of disease. However, facial coverings may impede ventilation during high-intensity activity, leading to a reduction in cardiopulmonary exercise capacity. Thus, the purpose of this study was to determine the acute impact of different facial coverings on exercise performance in college-aged individuals during a 300-yard shuttle. It was hypothesized that the lowest heart rate (HR), completion time (CT), and rate of perceived exertion (RPE) would occur with no mask. Furthermore, it was hypothesized the SHEMA97 mask would have lower HR, CT, and RPE compared to surgical and fabric masks. Results showed the use of the fabric mask resulted in significantly higher HR compared to no mask (p = 0.006). The SHEMA97 mask resulted in faster CT and lower RPE compared to both the fabric and surgical masks (p < 0.001). All mask conditions yielded significantly higher levels of perceived discomfort than wearing no mask (p < 0.05). While the use of facial coverings can help prevent the spread of disease, their use during exercise may pose limitations to performance; however, the ability of the SHEMA97 to provide minimal changes to CT and RPE provides a promising option.

Validation of the Polar Team Pro System for Sprint Speed With Ice Hockey Players.

ABSTRACT: Conners, RT, Whitehead, PN, Dodds, FT, Schott, KD, and Quick, MC. Validation of the polar team pro system for sprint speed with ice hockey players. J Strength Cond Res 36(12): 3468-3472, 2022-Commercially available player tracking sensors such as the Polar Team Pro system (PTPS) have been used to monitor athlete performance. Use during ice hockey practices and games has resulted in seemingly plausible and valid values for internal metrics (heart rate); however, external metrics (distance, speed, and acceleration) seem sporadic and counterintuitive. To determine the validity of the PTPS for measuring sprint speed with collegiate hockey players, 15 NCAA Division I male athletes (21.86 ± 1.04 years, 175.86 ± 6.78 cm, 80.58 ± 4.44 kg) participated in the study. Subjects wore a PTPS strap, at the level of the xiphoid process, and performed 2 sprints of 15.24 m (blue line to blue line) and 35.05 m (red line to the far blue line) in 3 conditions: indoor ice skating, indoor running, and outdoor running. Timing gates (TG) were used to determine sprint times, which allowed for manual calculation of speed. Speed values from the PTPS and TG were compared using paired-samples t -tests, and an alpha level of 0.05, 2-sided, was set a priori as a significance level. For indoor ice skating, PTPS significantly underestimated speeds at both distances ( p < 0.001). However, PTPS significantly overestimated speeds for indoor and outdoor sprints at both distances ( p ≤ 0.001). The PTPS is not accurate for measuring short-distance linear sprint speed or linear sprint speed during indoor ice skating. The inconsistency in speed values needs to be taken into consideration when using the system for science-based training because inaccurate speed values may negatively affect other external performance metrics provided by PTPS.

An Evolving Approach to Assessing Cardiorespiratory Fitness, Muscle Function and Bone and Joint Health in the COVID-19 Era.

Cardiorespiratory fitness (CRF) is now an established vital sign. CRF, along with muscle function and bone and joint health is related to functional independence and a higher quality of life. Wasserman and colleagues proposed a gear model illustrating the integrated role of the respiratory, cardiovascular, and skeletal muscle systems during aerobic exercise; in 2015, a revision to the original model was proposed. Our understanding of the effects and challenges associated with the coronavirus disease 2019 (COVID-19) are rapidly evolving. Initial evidence indicates higher levels of CRF, and muscle function protect individuals infected with COVID-19 from a complicated medical course. Moreover, for those individuals infected with COVID-19, there are initial signs of a reduction in CRF following the initial phase of recovery. We are also gaining an understanding of long COVID syndrome, where individuals who have recovered from the acute phase of viral infection present with lasting symptoms, which include but are not limited to reduced CRF, shortness of breath, and fatigue. Clearly, these individuals will require rehabilitation to restore and/or improve CRF, muscle function, bone and joint health, functional capacity (ie, the ability to perform activities of daily living), and quality of life. The importance of assessing the synergistic function of systems essential to performing activities that require physical exertion is a health care imperative. This graphical narrative provides an update to the gear model initially proposed by Wasserman and updated to a gear and circuit in 2015. External CRF, muscle function, and bone and joint health influencers and an approach to clinical assessment are also introduced.

Current and Future Implications of COVID-19 among Youth Wheelchair Users: 24-Hour Activity Behavior.

Preventative measures taken worldwide to decrease the transmission of COVID-19 have had a tremendous impact on youth. Following social restrictions, youth with and without physical disabilities are engaging in less physical activity, more increased sedentary behavior, and poor sleep habits. Specifically, youth wheelchair users (YWU) are likely disproportionately affected by COVID- 19 and have a higher risk of contraction due to underlying comorbidities. While we cannot control all of the negative long-term implications of COVID-19 for YWU, participation in positive 24-h activity behaviors can decrease chronic disease risk and the likelihood of long-term complications resulting from infection. This commentary is to extend the discourse on the importance of 24-h activity behaviors by focusing on YWU. Specifically, we discuss the importance of chronic disease prevention, provide a brief overview of 24-h activity behaviors, and outline some of the lessons that can be learned from the COVID-19 pandemic.

Kinematic analysis of gait in an underwater treadmill using land-based Vicon T 40s motion capture cameras arranged externally.

Aquatic therapy for rehabilitation can be performed in a variety of environments, which can vary from a traditional swimming pool to a self-contained underwater treadmill. While kinematic analysis has been performed in large volume swimming pools using specific underwater motion capture systems, researchers may only have access to a land-based motion-capture system, which is not waterproof. Additionally, underwater motion capture systems may not fit within the confines of a smaller underwater treadmill. Thus, the purpose of this study was to design and analyze methodology to quantify lower limb kinematics during an aquatic treadmill session, using a land-based motion capture system. Kinematics of lower limb motion at different speeds was studied while walking on an underwater treadmill in comparison to walking on the same treadmill without water (empty tank). The effects of the presence of water on walking kinematics was analyzed and interpreted using parametric and non-parametric testing procedures. The results suggest significant influences of speed on knee and ankle angles (p < 0.05) in both dryland and aquatic scenarios. Knee and ankle angle measures revealed no significant differences between the dryland and water treadmill scenarios (p > 0.05). The increased time requirement in water for the full gait cycle found in this study indicates influence of resistive effects. This finding can be especially suited for muscle strengthening and stabilizing treatments for lower limbs. Also, a framework was developed to realize a potential methodology to use land-based motion capture cameras to successfully analyze the kinematics of gait in constrained aquatic volumes.

Comparison of the Three-Site and Seven-Site Measurements in Female Collegiate Athletes Using BodyMetrix™.

One method to measure body composition that is gaining popularity is the BodyMetrix™, which uses A-mode ultrasound. A-mode ultrasound, when used with the BodyMetrix™, has been found to be a reliable and a cost-effective tool for measuring overall body fat percentage. Furthermore, the portability and short duration testing features of the BodyMetrix™, allows for testing of a large group of athletes inside or outside of a clinical setting. Despite these advantages, research regarding the BodyMetrix™ is limited and has primarily focused on the seven-site testing technique. However, the three-site technique allows for faster testing and a reduction of time needed to test an entire team or multiple sports teams. Thus, the purpose of this study was to compare the three-site and seven-site methods using the BodyMetrix™ to determine body fat percentage in female collegiate athletes. It was hypothesized that body fat percentage determined via the seven-site method would be different from those obtained by three-site measurement technique. Study participants included 40 National Collegiate Athletic Association (NCAA) Division-II female athletes from volleyball, soccer, and softball teams. The Jackson Pollock three-site (thigh, suprailiac, triceps) and seven-site (thigh, suprailiac, triceps, abdominal, subscapular, chest, and axilla) equations were used to determine body fat percentage values. The time required to perform the three-site and seven-site measurements were also recorded. A paired samples t-test was used to assess if there was a difference between the three-site and the seven-site body fat percentage measurements with the use of the BodyMetrix™ . The three-site method (23.21 ± 3.61) was significantly lower (p < 0.001) compared to the seven- site method (25.75 ± 4.39). On average, the three-site technique took 2 minutes and 13 seconds less than the seven-site technique.

Visual classification of running economy by distance running coaches.

AbstractObjectives: This study assessed the ability of coaches to rank-order distance runners on running economy (RE) through visual assessment. Methods: Running economy was measured in five trained recreational distance runners at a speed of 3.57 m·s-1, with a minimum VO2 difference of 2-mL.kg-1.min-1 between adjacent runners. Following measurement of RE, participants were filmed from the front, side, and rear while running on a treadmill. Endurance coaches from high school to international level (N = 121) viewed each video and ranked the runners on a scale from 1 (most economical) to 5 (least economical). Coaches also completed a demographic questionnaire and listed running style biomechanical observations they used in determining each ranking. A cumulative odds ordinal logistic regression with proportional odds was run to determine the effect of coaching level, years of coaching experience, years of training experience, competition level, certification status, and education level, on the ability of distance running coaching to accurately rank RE among a group of runners. Results: No coaching characteristic was a significant predictor of ranking accuracy, χ2 = 3.566, p = .735. Conclusions: Visual assessment of effort, based on RE, is a difficult task, even for the trained eye and could be related to difficulty in understanding the interaction effect of various RE factors or the translation of scientific-based knowledge to the field of play. Practically, coaches should be cautious when recommending biomechanical adjustments without considering the interconnected factors related to such changes.

Leisure time physical activity in persons with spinal cord injury across the seasons.

OBJECTIVES: The main goal of this study was to assess the level of leisure-time physical activity (LTPA) and its differentiation across the seasons among persons with spinal cord injury (SCI). The additional aim was to determine whether socio-demographical, injury, and seasonal factors are determinants of LTPA. METHODS: This study included 51 adults with SCI, who completed the LTPA questionnaire for persons with SCI during a calendar year in the middle of four seasons, and demographic questionnaire. A multiple regression analysis was used to examine the role of socio-demographical, injury, and seasonal variables, as determinants of LTPA. RESULTS: The levels of LTPA were differentiated throughout the seasons. Three models containing variables related to LTPA were created. All models were significant, for mild LTPA (F = 10.01, r 2 = 0.21), moderate LTPA (F = 5.24, r 2 = 0.9), and heavy LTPA (F = 7.09, r 2 = 0.6). Age at the time of study, lack of employment, tetraplegia, and shorter time since injury were significantly, negatively associated with LTPA. CONCLUSION: LTPA in persons with SCI differs significantly in relation to the seasons throughout a year. The season of the year should be considered in future studies and interventions on LTPA in adults with SCI.

Shoulder Strength and Range of Motion Between Collegiate Pitchers and Position Players in Baseball.

Baseball is a sport that places excessive strain on the shoulder complex caused from repetitive overhead throws. In the sport of baseball, shoulder strength and range of motion (ROM) are paramount for success on the field. The purpose of this study was to determine strength and ROM differences between collegiate baseball pitchers and position players. It was hypothesized that pitchers would have higher strength and ROM values, due to the volume of throwing a pitcher performs. A total of nine collegiate baseball pitchers and position players (n = 18) volunteered for the study (age = 20.94 ± 1.21 years, height = 183.42 ± 4.74 cm, and mass = 89.56 ± 10.76 kg). Shoulder strength was measured using a Humac Norm isokinetic dynamometer at 180ºsec-1 and 300ºsec-1 and ROM was measured using a goniometer. All participants completed a five-minute warm-up at 50 rpm on an upper body ergometer. Following the warm-up, passive internal and external ROM were measured for the throwing (dominant) arm. No statistical differences were found in external ROM (p = 0.319), internal ROM (p = 0.258), external peak torque @180ºsec-1 (p = 0.467), internal peak torque @180ºsec-1 (p = 0.156), external peak torque @300ºsec-1 (p = 0.225), or internal peak torque @300ºsec-1 (p = 0.137). The findings indicate similar isokinetic strength and flexibility in the throwing shoulder of collegiate athletes who perform repeated overhead throwing motions. Thus, in this study the player's baseball position (pitchers vs. position player) did not influence throwing shoulder strength and ROM characteristics.

The Effect of In-Season Demands on Lower-Body Power and Fatigue in Male Collegiate Hockey Players.

Whitehead, PN, Conners, RT, and Shimizu, TS. The effect of in-season demands on lower-body power and fatigue in male collegiate hockey players. J Strength Cond Res 33(4): 1035-1042, 2019-The purpose of this study was to determine the effect of in-season demands, such as games, travel, and the subsequent fatigue related to these demands, on lower-body power (LBP) in collegiate hockey players. Two jump protocols (countermovement and squat jumps) were used to calculate LBP. Twenty-seven NCAA (National Collegiate Athletic Association) Division I male hockey players (age, 21.9 ± 1.4 years; height, 176.7 ± 6.5 cm; body mass, 81.4 ± 7.9 kg) participated in the study that spanned 18 weekly sessions. At each session, participants completed an 8-item fatigue questionnaire, which provided a cumulative numerical value for fatigue (total score of fatigue [TSF]), before performing maximal jumps on a contact mat. General linear modeling was conducted to compare dependent variables (jump height, relative LBP, TSF) across weekly sessions. Pearson product-moment correlation coefficients were calculated to examine the relationship between jump height and LBP across the jump protocols, as well as to examine the relationship of TSF with all measured variables. Jump height and LBP declined throughout the season with greater effect of travel observed following the longest travel sequence (p ≤ 0.05; η ≥ 0.60). Differences in TSF were observed from baseline (p ≤ 0.037), and a large effect was seen for away trips that included air travel (d ≥ 1.35). Total score of fatigue had a negative correlation with jump height and power during both jumps (r ≤ -0.742; p < 0.001). In conclusion, the in-season demands of ice hockey resulted in significant reductions in LBP throughout a hockey season, and the 8-item fatigue questionnaire is a sensitive tool reflective of athletic performance measures.

Impact of Underwater Treadmill Training on Glycemic Control, Blood Lipids, and Health-Related Fitness in Adults With Type 2 Diabetes.

IN BRIEF A large number of adults with type 2 diabetes experience comorbidities that discourage physical activity and hinder regular participation in land-based exercise programs. An aquatic exercise program is an innovative exercise modality that incorporates combined aerobic and resistance exercise. The purpose of this study was to determine if an underwater treadmill walking program featuring gradual and progressive increases in walking speed and duration has a positive effect on glycemic control, metabolic health, cardiovascular function, body composition, and leg strength in middle-aged adults with type 2 diabetes.

The effect of running barefoot and in barefoot-style footwear on running economy at two self-determined speeds.

BACKGROUND: The impact of barefoot running and footwear choice on running economy (RE; steady state oxygen consumption) is heavily debated. Therefore, this study measured RE when running barefoot versus two shod conditions. METHODS: Recreational male runners (N.=8) with experience running in both five-toed minimal (FTMS) and standard cushioned running shoes (SCRS), participated in RE trials while barefoot, FTMS, and SCRS for 5 minutes each trial at both 50% and 70% of speed at maximal oxygen uptake (sVO2max), while RE and step frequency (Sf) were measured. Separate one-way repeated measures ANOVAs were conducted for each footwear condition and each speed, on RE and Sf. RESULTS: No significant differences in RE were found at 50% or 70% sVO2max. Step frequency was significantly different at 70% sVO2max (F(2, 14)=6.74, P=0.009, partial ω2=0.06, as running barefoot (173.00±10.50 steps/min) exhibited a higher Sf than running in FTMS (68.81±10.94 steps/min; P=0.008) or SCRS (166.62±8.42 steps/min; P=0.044) conditions. CONCLUSIONS: No statistical RE benefit was found when running barefoot over FTMS or SCRS, possibly explained by a Sf adaptation at higher speeds. However, practically speaking, when shoe mass is controlled for, footwear choice has a moderate but worthwhile effect on RE. Consequently, formal familiarization and/or training in the FTMS may improve RE when compared to running in SCRS or barefoot in certain individuals.

Association of physical activity and body mass index with metabolic syndrome among U.S. adolescents with disabilities.

BACKGROUND: Adolescents with disabilities (A-With-D) have shown to be less physically active and more obese compared to adolescents without disabilities (A-Without-D); however, little is known in regards to the impact of physical activity (PA) and body mass index (BMI) on metabolic syndrome (MetS) among A-with-D. OBJECTIVE: The purpose of this study was to compare the prevalence of MetS, PA levels and BMI percentile between A-With-D and A-Without-D, and to examine the influence of PA and BMI on MetS among A-With-D. METHODS: Data from the National Health and Nutrition Examination Survey 1999-2010 was used in this study. Inclusion criteria for the study consisted of those who indicated, in the survey, that they had received special education or early intervention service (n = 278). PA level was assessed subjectively by asking the amount of leisure time PA. BMI percentile was obtained using BMI growth charts by age and sex. The continuous MetS (cMetS) score was computed using age and sex standardized residual for mean arterial blood pressure, triglyceride, glucose, waist circumference, and high-density lipoprotein cholesterol. RESULTS: A-With-D were more likely to be obese and less likely to be engaged in PA compared to A-Without-D. A-With-D were less favorable to MetS with significantly higher cMetS scores than A-Without-D. Lower levels of PA and higher percentile of BMI were significantly associated with higher levels of cMetS scores among A-With-D. CONCLUSION: This study provided empirical evidence for the importance of promoting a healthy lifestyle (i.e., increasing the level of PA and decreasing the BMI percentile) among A-With-D in order to reduce the risk of MetS.