Purpose The commercial market is saturated with technologies that claim to collect proficient, free-living sleep measurements despite a severe lack of independent third-party evaluations. Therefore, the present study evaluated the accuracy of various commercial sleep technologies during in-home sleeping conditions. Materials and Methods Data collection spanned 98 separate nights of ad libitum sleep from five healthy adults. Prior to bedtime, participants utilized nine popular sleep devices while concurrently wearing a previously validated electroencephalography (EEG)-based device. Data collected from the commercial devices were extracted for later comparison against EEG to determine degrees of accuracy. Sleep and wake summary outcomes as well as sleep staging metrics were evaluated, where available, for each device. Results Total sleep time (TST), total wake time (TWT), and sleep efficiency (SE) were measured with greater accuracy (lower percent errors) and limited bias by Fitbit Ionic [mean absolute percent error, bias (95% confidence interval); TST: 9.90%, 0.25 (−0.11, 0.61); TWT: 25.64%, −0.17 (−0.28, −0.06); SE: 3.49%, 0.65 (−0.82, 2.12)] and Oura smart ring [TST: 7.39%, 0.19 (0.04, 0.35); TWT: 36.29%, −0.18 (−0.31, −0.04); SE: 5.42%, 1.66 (0.17, 3.15)], whereas all other devices demonstrated a propensity to over or underestimate at least one if not all of the aforementioned sleep metrics. No commercial sleep technology appeared to accurately quantify sleep stages. Conclusion Generally speaking, commercial sleep technologies displayed lower error and bias values when quantifying sleep/wake states as compared to sleep staging durations. Still, these findings revealed that there is a remarkably high degree of variability in the accuracy of commercial sleep technologies, which further emphasizes that continuous evaluations of newly developed sleep technologies are vital. End-users may then be able to determine more accurately which sleep device is most suited for their desired application(s).

Comparisons of countermovement jump force-time characteristics among NCAA Division I American football athletes: use of principal component analysis. J Strength Cond Res 36(2): 411-419, 2022-This study aimed to reduce the dimensionality of countermovement jump (CMJ) force-time characteristics and evaluate differences among positional groups (skills, hybrid, linemen, and specialists) within National Collegiate Athletic Association (NCAA) division I American football. Eighty-two football athletes performed 2 maximal effort, no arm-swing, CMJs on force plates. The average absolute and relative (e.g., power/body mass) metrics were analyzed using analysis of variance and principal component analysis procedures (p , 0.05). Linemen had the heaviest body mass and produced greater absolute forces than hybrid and skills but had lower propulsive abilities demonstrated by longer propulsive phase durations and greater eccentric to concentric mean force ratios. Skills and hybrid produced the most relative concentric and eccentric forces and power, as well as modified reactive strength indexes (RSI MOD ). Skills (46.7 6 4.6 cm) achieved the highest jump height compared with hybrid (42.8 6 5.5 cm), specialists (38.7 6 4.0 cm), and linemen (34.1 6 5.3 cm). Four principal components explained 89.5% of the variance in force-time metrics. Dimensions were described as the (a) explosive transferability to concentric power (RSI MOD , concentric power, and eccentric to concentric forces) (b) powerful eccentric loading (eccentric power and velocity), (c) countermovement strategy (depth and duration), and (d) jump height and power. The many positional differences in CMJ forcetime characteristics may inform strength and conditioning program designs tailored to each position and identify important explanatory metrics to routinely monitor by position. The overwhelming number of force-time metrics to select from may be reduced using principal component analysis methods, although practitioners should still consider the various metric's applicability and reliability.

Despite prolific demands and sales, commercial sleep assessment is primarily limited by the inability to “measure” sleep itself; rather, secondary physiological signals are captured, combined, and subsequently classified as sleep or a specific sleep state. Using markedly different approaches compared with gold-standard polysomnography, wearable companies purporting to measure sleep have rapidly developed during recent decades. These devices are advertised to monitor sleep via sensors such as accelerometers, electrocardiography, photoplethysmography, and temperature, alone or in combination, to estimate sleep stage based upon physiological patterns. However, without regulatory oversight, this market has historically manufactured products of poor accuracy, and rarely with third-party validation. Specifically, these devices vary in their capacities to capture a signal of interest, process the signal, perform physiological calculations, and ultimately classify a state (sleep vs. wake) or sleep stage during a given time domain. Device performance depends largely on success in all the aforementioned requirements. Thus, this review provides context surrounding the complex hardware and software developed by wearable device companies in their attempts to estimate sleep-related phenomena, and outlines considerations and contributing factors for overall device success.

As sports technology has continued to develop, monitoring athlete workloads, performance, and recovery has demonstrated boundless benefits for athlete and team success. Specifically, technologies such as global positioning systems (GPS) and heart rate (HR) monitors have granted the opportunity to delve deeper into performance contributors, and how variations may exist based upon context. A team of NCAA Division I women’s soccer athletes were monitored during games throughout one competitive season. Individual athlete, positional groups, and team external and internal workloads were explored for differences based upon game location, opponent ranking, game result, and the final score differential. Game location and opponent ranking were found to have no effect on team-wide absolute or relative external workloads, whereas game result and score differential did. Internal workloads across the team tended to only vary by game half, independent of game context; however, the HR of defenders was determined to be higher during losses as compared to wins (p = 0.0256). Notably, the games that resulted in losses also represented the games with the fewest number of substitutions. These findings suggest high value in monitoring performance and workloads that are characteristic of varying, often multifaceted, contexts. It is hoped that this information can lead to more informed approaches to vital game-time and coaching decisions.

Research is emerging on the use of Photobiomodulation therapy (PBMT) and its potential for augmenting human performance, however, relatively little research exists utilizing full-body administration methods. As such, further research supporting the efficacy of whole-body applications of PBMT for behavioral and physiological modifications in applicable, real-world settings are warranted. The purpose of this analysis was to observe cardiorespiratory and sleep patterns surrounding the use of full-body PBMT in an elite cohort of female soccer players. Members of a women’s soccer team in a “Power 5 conference” of the National Collegiate Athletic Association (NCAA) were observed across one competitive season while wearing an OURA Ring nightly and a global positioning system (GPS) sensor during training. Within-subject comparisons of cardiorespiratory physiology, sleep duration, and sleep composition were evaluated the night before and after PBMT sessions completed as a standard of care for team recovery. Compared to pre-intervention, mean heart rate (HR) was significantly lower the night after a PBMT session (p = 0.0055). Sleep durations were also reduced following PBMT, with total sleep time (TST) averaging 40 min less the night after a session (p = 0.0006), as well as significant reductions in light sleep (p = 0.0307) and rapid eye movement (REM) sleep durations (p = 0.0019). Sleep durations were still lower following PBMT, even when controlling for daily and accumulated training loads. Enhanced cardiorespiratory indicators of recovery following PBMT, despite significant reductions in sleep duration, suggest that it may be an effective modality for maintaining adequate recovery from the high stress loads experienced by elite athletes.

This study was conducted to identify whether team-wide or positional differences exist in simple or choice reactivity of collegiate soccer athletes when completed under various loads. Much research exists surrounding the assessment of reaction time in the general population, but given variations in training, little insight exists surrounding how unique and elite populations may differ based upon performance demands and task translatability to training. Reactive performance was assessed using the Dynavision D2 in 24 female soccer players (19.73 ± 1.05 years old) from a team within a power five conference of the National Collegiate Athletic Association. Evaluated loads included two conditions of simple reactivity (no additional load and with a concurrent lower body motor task) and three conditions of choice reactivity (no additional load, with a concurrent lower body motor task, and prolonged durations). Paired t-tests and ANOVAs were used to identify differences in task performance based upon load and positional group. No significant load-based or positional differences existed in measured simple reaction times. Performances in choice reaction tasks across the team were found to be slower when completed across extended durations (p < 0.0001) and faster when completed concurrent with an added balance task (p = 0.0108), as compared to performance under normal conditions. By assessment of positional differences, goalkeepers tended to be slower than other positions in reactivity during choice tasks, despite no differences existing in simple task performance. Given the unique population utilized herein, measured reactivity in different tasks suggests a strong relation to the training demands of soccer, as well as those of goalkeepers as compared to field positions. Findings suggest that sport and positional demands may be substantial contributors to population- and individual-based reactivity performance.

Prior research has identified lower muscle tissue CT attenuation in patients impacted by cancer cachexia. CT attenuation is a measure of tissue radiodensity, which in muscle, reflects the degree of myocellular fat and intramuscular fat infiltration. In contrast, PET imaging captures glucose uptake as quantified by the standardized uptake value (SUV). Collectively, CT and PET may provide an opportunity to identify tissue-specific differences that are associated with unintentional weight loss. This study utilized [18F-FDG] PET/CT imaging at multiple timepoints in cancer patients to investigate how adipose tissue and skeletal muscle properties change following cancer diagnosis and treatment. We hypothesized that longitudinal changes in CT attenuation and SUV adipose tissue and muscle would be more profound in cachectic individuals. Eighty-four patients (57M, 27F; 63.3±9.6 years; BMI 27.4±5.3) with stage 2 or 3 non-small cell lung cancer were imaged before and after chemoradiation treatment (162±32 days between scans). Pre- to post-treatment weight change averaged -4.93% (±9.6) normalized to six months, with 41 patients experiencing cachexia (defined as 5% weight loss in ≤6 months). CT attenuation (HU) and mean SUV normalized to body mass index were compared pre- to post-treatment. Pre-treatment, CT attenuation was higher in the non-cachectic group for the gluteus maximus (p=0.0087) and pectoralis major (p=0.0479), but not the erector spinae or subcutaneous adipose tissue (SAT). SUV was higher pre-treatment in the cachectic group in the erector spinae (p=0.0103) and gluteus maximus (p=0.0035); no group differences in the pectoralis major or SAT. Pre- to post-treatment decreases in CT attenuation occurred only in the non-cachectic group of the pectoralis major (p<0.0001), despite no changes in either group in the erector spinae, gluteus maximus or SAT. Post-treatment increases in SUV were seen in the non-cachectic group only for the erector spinae (p=0.0075) and gluteus maximus (p=0.0209), and both groups for the pectoralis major (cachectic, p=0.0333; non-cachectic, p=0.0304). In contrast, post-treatment increases in SUV only occurred in the cachectic group (p=0.0057). Findings suggest that both CT and PET can provide differential value in monitoring cancer induced changes to non-malignant tissues; changes in tissue composition, quantified via CT, are not linear with changes in metabolism, measured via PET. Further, the PET/CT profiles of all muscle groups do not initially exist or change in the same manner, which may correspond to variability in fiber type composition or function. Pre-treatment evaluation of adipose and muscle properties using both PET and CT could be useful for stratifying vulnerability to unintentional weight loss, allowing for early application of exercise and nutritional interventions. This research was funded by NIAMS (R01AR079445; Pistilli) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Both macro and micronutrient intakes have an impact on sleep behaviors in athletes, notably sleep onset latency and sleep efficiency. Proper nutrient intake supports daily muscle repair and synthesis of sleep regulating compounds (e.g., serotonin and melatonin). The objective of this study was to evaluate the relationship between sleep behaviors and dietary intake in elite college female athletes. It was hypothesized that dietary carbohydrates and vitamin intake would be associated with both sleep timing and consistency. Twenty-three female Division I collegiate soccer players were evaluated for their sleep and nutritional patterns. Athletes wore an OURA ring (OURA Health, Oulu, Finland) each night for 31 days during the competitive season. During the final three days, athletes recorded their dietary intake using the Automated Self-Administered 24-hour Dietary Assessment Tool (ASA24). All athletes were exposed to the same travel schedule throughout the evaluation period, which did not differ by more than one time zone. Pearson’s R with Bonferonni Correction was used to assess the relationship between the average daily intake of various nutrients with average nightly sleep behaviors. Total Vitamin B12 ( r=-0.63), added Vitamin B12 ( r=-0.62), and Vitamin C ( r=-0.53) were negatively correlated with average bedtimes (P<0.01) while added Vitamin B12 ( r=-0.61) and Vitamin C ( r=-0.50) were also negatively associated with wake times (P<0.01). Greater dietary intake of kcals from carbohydrates, with respect to recommended consumption, was associated with earlier bedtimes ( r=0.41, P<0.05). In conclusion, greater intake of carbohydrates and vitamins B12 and C are associated with ideal sleep behaviors. A potential mechanism accounting for this relationship could be the enhanced contribution of antioxidants and glycemic load on the synthesis of vital hormones for sleep regulation, including serotonin and melatonin. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.