Stryd 25 vs. Stryd 27: Comparing Running Metrics Between a Predecessor and “The Next Gen Stryd”

Wearable technology has claimed the top spot in the Worldwide Survey of Fitness Trends in all but two years since 2016. A popular wearable among runners is the Stryd power meter. The company markets its latest model, the Stryd 27, as 5x more responsive in measuring running power. Yet, it is unclear whether the new model performs differently than its predecessor. PURPOSE: This study aimed to compare running metrics of the Stryd 25 and Stryd 27 in self-paced and interval runs. METHODS: Participants consented (N = 16; 50% female; height = 174.1 ± 8.1 centimeters [cm]; mass = 73.0 ± 12.4 kilograms) and were equipped with the Stryd 25 and Stryd 27, attached randomly to the left and right shoelaces. Each Stryd was paired with a separate mobile device using the Stryd app. Researchers started and stopped recording on each Stryd simultaneously. Participants ran for 10 minutes at a self-selected pace counterclockwise around an indoor track (10 laps/mile) before resting for five minutes. Then participants ran 10 more minutes, alternating between fast and slow intervals: 120 seconds (s) × 2, 60 s × 2, 30 s × 4, and 15 s × 8. Fast and slow intervals were 20% faster and 20% slower, respectively, than the participant’s mean pace of the first run. The Stryd app recorded power in watts (W), cadence in steps per minute (spm), vertical oscillation (VO) in cm, and stride length in meters (m). Four independent t-tests were run to compare these measurements between the two Stryd models for the self-paced and interval runs. The alpha level was .05, and the effect size was Cohen’s d (0.2 small, 0.5 medium, 0.8 large). RESULTS: See Table 1. CONCLUSION: Four running metrics were statistically similar between the Stryd 25 and Stryd 27 during two indoor runs. Runners using the predecessor indoors can be confident it returns similar data to the newest model

Assessing the Reliability of Stryd 27 for Variable Speed Running

Wearable technology is beneficial when it comes to tracking and optimizing performance. The Stryd 27 is a wearable footpod marketed as being more responsive in measuring power during running than the previous version (Stryd 25). However, the reliability of this newer device to return consistent values has not been determined. PURPOSE: This study aimed to observe whether Stryd 27 gives reliable metrics during variable speed running. METHODS: Sixteen participants (N = 16; 50% female; height = 174.1 ± 8.1 cm; mass = 73.0 ± 12.4 kg) were recruited, each equipped with two Stryd 27 footpods (updated to the same software version) affixed to the shoelaces of their running shoes. The researchers recorded data using the Stryd app on a mobile device that was connected to the Stryd 27 via Bluetooth. Recording on both devices were started and stopped at the same time. Each participant completed two, 10-minute runs on an indoor track. The initial run was used to establish a baseline. Following a 5-minute rest period, participants proceeded with the second run, during which they alternated between faster and slower intervals. The pace for these intervals was set to be 20% faster and 20% slower than what each participant’s average pace was during the first run. Reliability of power, cadence, form power, ground contact time (GCT), vertical oscillation (VO), leg spring stiffness (LSS), and stride length during the interval run was determined using coefficient of variation (CV) and intraclass correlation coefficient (ICC), with CV0.70 (p \u3c 0.05) being considered evidence of reliability. RESULTS: Reliability data are shown in Table 1. The following measures were found to be reliable: power, cadence, form power, GCC, and VO. The measures of LSS and stride length were not found to be reliable. CONCLUSION: Runners using the new Stryd 27 can have confidence that most measures return reliable values (power, cadence, form power, GCT, and VO). Unfortunately, two measures were observed to not meet the threshold for reliability (LSS and stride length). Athletes interested in these measures should be cautious when interpreting their data

The Effectiveness of Running Power as a Metric of Exercise Intensity During Running Interval Training

Wearable power meters are increasingly popular among runners with Coros and Stryd offering running power as a real-time, trackable of a metric. PURPOSE: This study compared running power (RP) to physiological measures, heart rate (HR) and oxygen consumption (VO2), across high and low intensity running intervals. METHODS: Thirteen adult participants (n = 6 male; height = 174.9 ± 6.9 cm; mass = 72.5 ± 12.0 kg) were equipped with a Stryd 27 RP meter, a Polar H10 HR monitor, and a Cosmed K5 portable metabolic unit. Participants’ self-selected RP was obtained during a 10-min run on an indoor track (10 laps/mile). After resting for five minutes, participants ran another 10 min, alternating between equal intervals of RP 20% higher and 20% lower than self-selected RP: 120 s × 2, 60 s × 2, 30 s × 4, and 15 s × 8. All devices were started simultaneously before each run. RP (W/kg) was sampled at 1 Hz. HR (bpm) and VO2 (mL/kg/min) were sampled at 0.1 Hz throughout the interval run. Data were analyzed from the 60 s mark through the end of the run. HR and VO2 data were interpolated to 1 Hz, and cross correlations (max lag = 60 s) were used to compare RP, HR, and VO2 (mean values in Table 1). RESULTS: There were weak to moderate correlations between RP and VO2 (r = 0.351; lag = -29.1 s), RP and HR (r = 0.475; lag = 9.38 s), and HR and VO2 (r = 0.572; lag = -29.1 s; Table 2). CONCLUSION: HR showed the strongest correlation and smallest time delay with RP. This may be practically useful because HR data is more readily available to runners than VO2. However, the correlation is only moderate. While related, the three metrics of running intensity are fundamentally different. When exercising at a moderate intensity, changes in HR or VO2, which take seconds to minutes to stabilize, may be less evident than changes in mechanical power, which are immediate. Thus, it is possible that HR and VO2 would show a stronger relationship with RP across intervals longer than the 120 s maximum observed here. While RP can be a useful metric, it may not be informative about physiological responses to running especially over short intervals or when running at high intensity

Heart Rate and Energy Expenditure Concurrent Validity of Identical Garmin Wrist Watches During Moderately Heavy Resistance Training

Consistent with previous years, ACSM has found that wearable technology and resistance training (RT) are two of the top 5 fitness trends in 2023. Our lab recently found that wrist-worn devices, such as Garmin Instinct, are neither valid nor reliable at measuring average or maximal heart rate (HR) or estimating energy expenditure (EE) following light intensity circuit RT. We postulated that the errors may have been due to the device’s algorithms assuming higher intensity during RT. PURPOSE: The purpose of this study was to determine the concurrent validity of identical Garmin Instinct wrist-watches to record valid measures of average and maximal HR as well as estimated EE following moderately heavy RT. METHODS: Twenty-one adult participants completed this study (n=10 female, n=11 male). Two Garmin Instinct wrist-watches were evaluated, along with the Polar H10 chest strap and Cosmed K5 portable metabolic unit as the criterion devices for average/maximal HR and EE, respectively. Participants completed 8 supersets of the reverse lunge and shoulder press exercises using dumbbells at a light (4 sets) and moderately heavy (4 sets) intensity with 1 superset of 6 repetitions per exercise (12 repetitions per superset) and 1 min rest between supersets. Data were analyzed for validity (Mean Absolute Percent Error [MAPE] and Lin’s Concordance Coefficient [CCC]), with predetermined thresholds of MAPE\u3c10% and CCC\u3e0.70. A one-way repeated measures ANOVA with Sidak post-hoc test was used to determine differences (p\u3c0.05). RESULTS: The identical Garmin Instinct devices were not considered valid for average HR (MAPE range: 36.5-81.6%; CCC range: 0.07-0.18), maximal HR (MAPE range: 18.6-18.8%; CCC range: 0.15-0.31), or estimated EE (MAPE range: 14.0-16.4%; CCC range: 0.08-0.32) compared to the criterion references. The devices were significantly different than each other for average HR (p=0.005), maximal HR (p\u3c0.001), and estimated EE (p\u3c0.0001). CONCLUSION: The wearable wrist-worn devices tested herein should not be utilized for accurate measurements of HR or EE during RT, and there are even differences between identical devices. People who RT while using these devices should do so with caution if wishing to utilize them for physiological measures

Rating of Perceived Exertion, Average Heart Rate, and Energy Expenditure Following Indoor and Outdoor Moderately Heavy Superset Resistance Training

Our lab recently found that light intensity circuit resistance training outdoors had a significantly lower perception of effort (RPE) compared to indoor resistance training, despite no physiological differences in heart rate and energy expenditure. However, no study has examined other intensities or set schemes in differing environmental settings. PURPOSE: To determine how indoor or outdoor environments effect rating of perceived exertion (RPE) following light and moderately heavy intensity superset resistance training in recreationally resistance trained adults. METHODS: Twenty-three adult participants completed this study (n=10 female, n=13 male; age: 26.1±8.8 yrs; height: 172.2±9.5 cm; mass: 73.4±18.7 kg; RT experience: 5.3±4.8 yrs). Participants wore devices to measure heart rate (Polar H10 chest strap) and energy expenditure (Cosmed K5 Portable Metabolic Cart). Randomly in indoor and outdoor settings, participants completed 4 supersets of the reverse lunge and shoulder press exercises using dumbbells at a light (2 sets) and moderately heavy (2 sets) intensity with 1 superset of 6 repetitions per exercise (12 repetitions per superset) and 1 min rest between supersets. The OMNI Rating of Perceived Exertion Scale for Resistance Exercise 0-10 RPE scale was used following each superset. A paired T-test was used to determine differences between environmental setting (pRESULTS: No significant differences were observed between indoor and outdoor environments for average heart rate (129.4±17.2 and 127.8±23.3 bpm, p=0.67), energy expenditure (30.6±11.5 and 28.3±9.9 kcals; p=0.06), as well as RPE during light intensity (2.9±0.9 and 2.9±0.8 arbitrary units/AU’s, p=0.70) and moderately heavy intensity (6.5±1.7 and 6.3±1.5 AU’s, p=0.27) supersets. CONCLUSION: In recreationally resistance trained adults, light intensity and moderately heavy intensity superset resistance training in indoor or outdoor settings does not alter heart rate, energy expenditure, or perceived effort

Perceived Fatigue and Physical Activity Enjoyment Following Indoor and Outdoor Moderately Heavy Superset Resistance Training

ACSM has again determined that resistance training (RT) and outdoor activities are two of the top ten worldwide fitness trends for 2023. We previously found that RT outdoors had a significantly lower perception of effort (RPE) compared to indoor RT, despite no physiological differences in heart rate (HR) and energy expenditure (EE). However, no study has examined other feelings during RT in indoor or outdoor settings. PURPOSE: To determine how indoor or outdoor environments effect perceptions of fatigue and physical activity enjoyment following RT in recreationally resistance trained adults. METHODS: Twenty-three adult participants (n=10 female, n=13 male) completed this study. The Visual Analog Scale Fatigue (VAS-F) measured perceived fatigue and the Physical Activity Enjoyment Scale – Short Version (PACES-S) measured PA enjoyment, and both were measured at baseline and then immediately following an acute session of indoor or outdoor RT. HR was obtained from a chest strap (Polar H10) and EE from a Portable Metabolic Cart (COSMED K5). Randomly in indoor and outdoor settings, participants completed 4 supersets of the reverse lunge and shoulder press exercises using dumbbells at a light (2 sets) and moderately heavy (2 sets) intensity with 1 superset of 6 repetitions per exercise and 1 min rest between supersets. A paired T-test (for HR & EE comparisons) or one-way repeated measures ANOVA with Sidak post-hoc test (for VAS-F & PACES-S comparisons) were used to determine differences (p\u3c0.05). RESULTS: No significant differences were observed between indoor and outdoor RT for the physiological variables of average HR (129.4±17.2 and 127.75±23.3 bpm, respectively, p=0.66) and EE (30.6±11.5 and 28.3±9.9 kcals, respectively, p=0.06). Perceived fatigue significantly (p\u3c0.0001) increased from baseline (1.13±0.94 arbitrary units, AU’s) following indoor (4.54±1.91 AU’s) and outdoor (3.99±1.54 AU’s) RT, but no environmental differences (p=0.36) were observed. PA enjoyment was not significantly (p range: 0.27-0.93) different between baseline (18.73±1.83 AU’s) and following indoor (18.18±1.99 AU’s) or outdoor (18.36±1.99 AU’s) RT. CONCLUSION: In recreationally resistance trained adults, moderately heavy superset RT in indoor or outdoor settings does not alter perceived fatigue or physical activity enjoyment

Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

SARS-CoV-2 Omicron is an immune escape variant with an altered cell entry pathway

Vaccines based on the spike protein of SARS-CoV-2 are a cornerstone of the public health response to COVID-19. The emergence of hypermutated, increasingly transmissible variants of concern (VOCs) threaten this strategy. Omicron (B.1.1.529), the fifth VOC to be described, harbours multiple amino acid mutations in spike, half of which lie within the receptor-binding domain. Here we demonstrate substantial evasion of neutralization by Omicron BA.1 and BA.2 variants in vitro using sera from individuals vaccinated with ChAdOx1, BNT162b2 and mRNA-1273. These data were mirrored by a substantial reduction in real-world vaccine effectiveness that was partially restored by booster vaccination. The Omicron variants BA.1 and BA.2 did not induce cell syncytia in vitro and favoured a TMPRSS2-independent endosomal entry pathway, these phenotypes mapping to distinct regions of the spike protein. Impaired cell fusion was determined by the receptor-binding domain, while endosomal entry mapped to the S2 domain. Such marked changes in antigenicity and replicative biology may underlie the rapid global spread and altered pathogenicity of the Omicron variant

Investigation of hospital discharge cases and SARS-CoV-2 introduction into Lothian care homes

Background The first epidemic wave of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in Scotland resulted in high case numbers and mortality in care homes. In Lothian, over one-third of care homes reported an outbreak, while there was limited testing of hospital patients discharged to care homes. Aim To investigate patients discharged from hospitals as a source of SARS-CoV-2 introduction into care homes during the first epidemic wave. Methods A clinical review was performed for all patients discharges from hospitals to care homes from 1st March 2020 to 31st May 2020. Episodes were ruled out based on coronavirus disease 2019 (COVID-19) test history, clinical assessment at discharge, whole-genome sequencing (WGS) data and an infectious period of 14 days. Clinical samples were processed for WGS, and consensus genomes generated were used for analysis using Cluster Investigation and Virus Epidemiological Tool software. Patient timelines were obtained using electronic hospital records. Findings In total, 787 patients discharged from hospitals to care homes were identified. Of these, 776 (99%) were ruled out for subsequent introduction of SARS-CoV-2 into care homes. However, for 10 episodes, the results were inconclusive as there was low genomic diversity in consensus genomes or no sequencing data were available. Only one discharge episode had a genomic, time and location link to positive cases during hospital admission, leading to 10 positive cases in their care home. Conclusion The majority of patients discharged from hospitals were ruled out for introduction of SARS-CoV-2 into care homes, highlighting the importance of screening all new admissions when faced with a novel emerging virus and no available vaccine