Purpose: The optimal load for maximal power output during hang power cleans (HPCs) from a mechanical perspective is the 1-repetition-maximum (1RM) load; however, previous research has reported otherwise. The present study thus aimed to investigate the underlying factors that determine optimal load during HPCs. Methods: Eight competitive Olympic weight lifters performed HPCs at 40%, 60%, 70%, 80%, 90%, 95%, and 100% of their 1RM while the ground-reaction force and bar/body kinematics were simultaneously recorded. The success criterion during HPC was set above parallel squat at the receiving position. Results: Both peak power and relative peak power were maximized at 80% 1RM (3975.7 [439.1] W, 50.4 [6.6] W/kg, respectively). Peak force, force at peak power, and relative values tended to increase with heavier loads (P < .001), while peak system velocity and system velocity at peak power decreased significantly above 80% 1RM (P = .005 and .011, respectively). There were also significant decreases in peak bar velocity (P < .001) and bar displacement (P < .001) toward heavier loads. There was a strong positive correlation between peak bar velocity and bar displacement in 7 of 8 subjects (r > .90, P < .01). The knee joint angle at the receiving position fell below the quarter-squat position above 70% 1RM. Conclusions: Submaximal loads were indeed optimal for maximal power output for HPC when the success criterion was set above the parallel-squat position. However, when the success criterion was defined as the quarter-squat position, the optimal load became the 1RM load.
Seiichiro Takei, Kuniaki Hirayama and Junichi Okada
Juliessa M. Pavon, Richard J. Sloane, Carl F. Pieper, Cathleen S. Colón-Emeric, David Gallagher, Harvey J. Cohen, Katherine S. Hall, Miriam C. Morey, Midori McCarty, Thomas L. Ortel and Susan N. Hastings
This study describes the availability of physical activity information in the electronic health record, explores how electronic health record documentation correlates with accelerometer-derived physical activity data, and examines whether measured physical activity relates to venous thromboembolism (VTE) prophylaxis use. Prospective observational data comes from community-dwelling older adults admitted to general medicine (n = 65). Spearman correlations were used to examine association of accelerometer-based daily step count with documented walking distance and with duration of VTE prophylaxis. Only 52% of patients had documented walking in nursing and/or physical therapy/occupational therapy notes during the first three hospital days. Median daily steps recorded via accelerometer was 1,370 (interquartile range = 854, 2,387) and correlated poorly with walking distance recorded in physical therapy/occupational therapy notes (median 33 feet/day [interquartile range = 12, 100]; r = .24; p = .27). Activity measures were not associated with use or duration of VTE prophylaxis. VTE prophylaxis use does not appear to be directed by patient activity, for which there is limited documentation.
Zhen Zeng, Christoph Centner, Albert Gollhofer and Daniel König
Purpose: Setting the optimal cuff pressure is a crucial part of prescribing blood-flow-restriction training. It is currently recommended to use percentages of each individual’s arterial occlusion pressure, which is most accurately determined by Doppler ultrasound (DU). However, the practicality of this gold-standard method in daily training routine is limited due to high costs. An alternative solution is pulse oximetry (PO). The main purpose of this study was to evaluate validity between PO and DU measurements and to investigate whether sex has a potential influence on these variables. Methods: A total of 94 subjects were enrolled in the study. Participants were positioned in a supine position, and a 12-cm-wide cuff was applied in a counterbalanced order at the most proximal portion of the right upper and lower limbs. The cuff pressure was successively increased until pulse was no longer detected by DU and PO. Results: There were no significant differences between the DU and PO methods when measuring arterial occlusion pressure at the upper limb (P = .308). However, both methods showed considerable disagreement for the lower limbs (P = .001), which was evident in both men (P = .028) and women (P = .008). No sex differences were detected. Conclusions: PO is reasonably accurate to determine arterial occlusion pressure of the upper limbs. For lower limbs, PO does not seem to be a valid instrument when assessing the optimal cuff pressure for blood-flow-restriction interventions compared with DU.
Ian M. Greenlund, Piersan E. Suriano, Steven J. Elmer, Jason R. Carter and John J. Durocher
Background: Sedentary activity and sitting for at least 10 hours per day can increase the risk for cardiovascular disease by more than 60%. Use of standing desks may decrease sedentary time and improve cardiovascular health. Acute standing lowers pulse wave velocity (PWV), but chronic effects remain unknown. The purpose of this study was to determine the effect of chronic standing desk use on arterial stiffness versus seated controls. Methods: A total of 48 adults participated in this study. Twenty-four participants qualified as seated desk users (age 41  y, body mass index 25  kg/m2) and 24 as standing desk users (age 45  y, body mass index 25  kg/m2). Arterial stiffness was assessed as PWV within the aorta, arm, and leg. Results: Carotid–femoral PWV (cfPWV) was not different between seated (6.6 [1.3] m/s) and standing (6.9 [1.3] m/s) groups (P = .47). Similarly, there were no differences in arm or leg PWV between groups (P = .13 and P = .66, respectively). A secondary analysis of traditional factors of age and aerobic fitness revealed significant differences in cfPWV in seated and standing desk participants. Age also significantly influenced cfPWV across conditions. Conclusions: Standing for >50% of a workday did not affect PWV. Consistent with previous research, fitness and age are important modulators of arterial stiffness.
Kelly Cornett, Katherine Bray-Simons, Heather M. Devlin, Sunil Iyengar, Patricia Moore Shaffer and Janet E. Fulton
Artur Direito, Joseph J. Murphy, Matthew Mclaughlin, Jacqueline Mair, Kelly Mackenzie, Masamitsu Kamada, Rachel Sutherland, Shannon Montgomery, Trevor Shilton and on behalf of the ISPAH Early Career Network
Increasing population levels of physical activity (PA) can assist in achieving the United Nations sustainable development goals, benefiting multiple sectors and contributing to global prosperity. Practices and policies to increase PA levels exist at the subnational, national, and international levels. In 2018, the World Health Organization launched the first Global Action Plan on Physical Activity (GAPPA). The GAPPA provides guidance through a framework of effective and feasible policy actions for increasing PA, and requires engagement and advocacy from a wide spectrum of stakeholders for successful implementation of the proposed actions. Early career professionals, including researchers, practitioners, and policymakers, can play a major role with helping “all people being regularly active” by contributing to 4 overarching areas: (1) generation—of evidence, (2) dissemination—of key messages and evidence, (3) implementation—of the evidence-based actions proposed in the GAPPA, and (4) contributing to advocacy for robust national action plans on PA. The contribution of early career professionals can be achieved through 5 pathways: (1) research, (2) workplace/practice, (3) business, (4) policy, and (5) professional and public opinion. Recommendations of how early career professionals can contribute to the generation, dissemination, and implementation of the evidence and actions proposed by the GAPPA are provided.
Brianna J. Stubbs, Pete J. Cox, Tom Kirk, Rhys D. Evans and Kieran Clarke
Exogenous ketone drinks may improve athletic performance and recovery, but information on their gastrointestinal tolerability is limited. Studies to date have used a simplistic reporting methodology that inadequately represents symptom type, frequency, and severity. Herein, gastrointestinal symptoms were recorded during three studies of exogenous ketone monoester (KME) and salt (KS) drinks. Study 1 compared low- and high-dose KME and KS drinks consumed at rest. Study 2 compared KME with isocaloric carbohydrate (CHO) consumed at rest either when fasted or after a standard meal. Study 3 compared KME+CHO with isocaloric CHO consumed before and during 3.25 hr of bicycle exercise. Participants reported symptom type and rated severity between 0 and 8 using a Likert scale at regular intervals. The number of visits with no symptoms reported after ketone drinks was n = 32/60 in Study 1, n = 9/32 in Study 2, and n = 20/42 in Study 3. Following KME and KS drinks, symptoms were acute but mild and were fully resolved by the end of the study. High-dose KS drinks caused greater total-visit symptom load than low-dose KS drinks (13.8 ± 4.3 vs. 2.0 ± 1.0; p < .05) and significantly greater time-point symptom load than KME drinks 1–2 hr postdrink. At rest, KME drinks caused greater total-visit symptom load than CHO drinks (5.0 ± 1.6 vs. 0.6 ± 0.4; p < .05). However, during exercise, there was no significant difference in total-visit symptom load between KME+CHO (4.2 ± 1.0) and CHO (7.2 ± 1.9) drinks. In summary, exogenous ketone drinks cause mild gastrointestinal symptoms that depend on time, the type and amount of compound consumed, and exercise.
Jordan Andre Martenstyn, Lauren Powell, Natasha Nassar, Mark Hamer and Emmanuel Stamatakis
Background: Previous epidemiological studies examining the association between physical activity (PA) and mortality risk have measured absolute PA intensity using standard resting metabolic rate reference values that fail to consider individual differences. This study compared the risk of all-cause and cardiovascular mortality between absolute and corrected estimates of PA volume. Methods: 49,982 adults aged ≥40 years who participated in the Health Survey for England and Scottish Health Survey in 1994–2008 were included in our study. PA was classified as absolute or corrected metabolic equivalent (MET)-hours per week, taking participant’s weight, height, age, and sex into account. Cox regression models were used to examine the association between absolute and corrected PA volumes and all-cause and cardiovascular mortality. Results: The authors found no difference in the association between levels of PA and risk of all-cause and cardiovascular mortality for absolute and corrected MET-hours per week, although there was a consistent decrease in mortality risk with increasing PA. There was no difference in mortality when analyses were stratified by sex, age, and body mass index. Conclusions: The association between PA volume and risk of mortality was similar regardless of whether PA volume was estimated using absolute or corrected METs. There is no empirical justification against the use of absolute METs to estimate PA volume from questionnaires.
Stephen S. Cheung
Jeanette Gustat, Christopher E. Anderson, Keelia O’Malley, Tian Hu, Rachel G. Tabak, Karin Valentine Goins, Cheryl Valko, Jill S. Litt and Amy A. Eyler
Background: To assess how perceptions of the community built environment influence support for community policies that promote physical activity (PA). Methods: A national cross-sectional survey assessed perceptions of the local built environment and support of community policies, including school and workplace policies, promoting PA. A random digit–dialed telephone survey was conducted in US counties selected on Behavioral Risk Factor Surveillance System data for high or low prevalence of obesity and inactivity. A total of 1208 subjects were interviewed, 642 from high-prevalence counties and 566 from low-prevalence counties. Analyses were stratified by county prevalence of obesity and inactivity (high or low). Linear models adjusted for covariates were constructed to assess the influence of built environment perceptions on policy support. Results: Perception of more destinations near the residence was associated with increased support for community policies that promote PA, including tax increases in low-prevalence (obesity and inactivity) counties (P < .01). Positive perception of the workplace environment was associated (P < .001) with increased support for workplace policies among those in high-, but not low-, prevalence counties. Conclusions: Support for community policies promoting PA varies by perception of the built environment, which has implications for policy change.