Acute Effects of Different Stretching Protocols Combined with Potentiating Exercise on Flexibility, Power, and Muscle Performance

The purpose of this study was to investigate the acute effects of different stretching protocols combined with potentiating exercise on flexibility, power, and muscle performance. This study was conducted in repeated and cross-over designed. Thirteen collegiate males aged 25.4±3.46 years voluntarily participated in this study. Prior to conduct stretching session, participants performed jogging on the treadmill for 5 min. Then, four different stretching protocols (non stretching; NS, static stretching; SS, dynamic stretching; DS, and proprioceptive neuromuscular facilitation stretching; PNFS) specially targeted for lower limb muscles combined with potentiating exercise (PE, 3 sets x 5 times tuck jumps) were randomly applied at the same time of the day with 7-days interval. Straight leg raise, and vertical jump tests were measured at baseline, post jogging, stretching, and potentiating exercise. Isokinetic muscle strength, anaerobic power, and agility T-test were measured after each stretching combined with potentiating exercise. Repeated measure ANOVAs were used with significant level set at p\u3c.05. Our results indicate that greater improvement in straight leg raise was observed in SS (9.6%) and PNFS (12.1%) compared to NS (0.6%) and DS (5.0%) at post stretching (p\u3c.001). However, vertical jump performance was significantly improved only in DS (1.8%) (p\u3c.001). After potentiating exercise, greater improvement of vertical jump performance was observed in NS (2.2%), SS (3.2%), and PNFS (6.5%) than DS (-0.4%) (p\u3c.01). Isometric leg flexion was significantly higher in DS and PNFS than NS and SS after completion of PE (p\u3c.05). However, no significant differences in leg extension, anaerobic power, and agility were observed among trials. Our study demonstrated that dynamic and PNF stretching protocols combined with potentiating exercise are efficient for generating muscle strength as well as improving flexibility. It is also noted that potentiating exercise plays a major role for preventing the acute loss of power induced by static and PNF stretching

Impact of placement of fitbit HR under laboratory and free-living conditions

© 2020 by the authors. Wrist-worn activity monitors have become accessible for measuring physical activities, but an activity monitor\u27s accuracy worn at different placements is not well understood. This study aimed to examine the differences in measurements of heart rates, step counts, and calories estimated from the fitness tracker worn at different locations and the accuracy of Fitbit HR against criterion measures. Thirty-two healthy adults participated in this study. Participants wore Fitbit HR at four different locations (right proximal, distal, and left proximal, distal). Treadmill exercise consisted of five 5-min phases including slow walking and jogging. Free-living activities involved ten 5-min activities with four different intensities. We found that the placement of Fitbit HR has no significant influence on the measurement outcomes overall. However, significant differences were observed in the step counts between left and right while climbing stairs (p = 0.003) and sports activities (p \u3c 0.001). The accuracy of Fitbit HR measurements against the criterion measure was moderate. However, we found out that Fitbit HR overestimated the calories regardless of their positions and activity types. In conclusion, the different placements of Fitbit HR do not have a significant influence on the measurements and Fitbit HR was moderately associated with criterion reference devices for measures of heart rate and steps

The Effects of High-Intensity Interval Training vs. Moderate-Intensity Continuous Training on Heart Rate Variability in Physically Inactive Adults

Physically inactive adults are prevalent worldwide. This study compared the effects of short-term high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on heart rate variability (HRV) in physically inactive adults as a preliminary study. Thirteen physically inactive male adults (27.5 ± 3.80 years) were randomly assigned to HIIT (N = 7) or MICT (N = 6). The HIIT program consisted of 20 min of interval training with cycling to rest ratio of 10/50 s at ≥90% HRpeak, while the MICT program consisted of 40 min of continuous cycling at 60–75% HRpeak. Both groups completed eight sessions of training within two weeks. Time and frequency domains of HRV were measured for 20 min with Actiwave-Cardio monitor (CamNtech, UK). The number of R-R interval and inter-beat interval (IBI) were significantly improved (p \u3c 0.05) in both HIIT and MICT programs following eight sessions of training. A significant interaction effect for group by time was found in the lnLF/HF ratio (p \u3c 0.05) where it was only improved in the HIIT group from pre- to post-test. The HIIT program is superior to MICT in improving HRV in physically inactive adults. The HIIT program can be applied as a time-efficient program for improving cardiac-autoregulation

Effect of Exercise Intervention on Flow-Mediated Dilation in Overweight and Obese Adults: Meta-Analysis

The objective of this meta-analysis is to summarize the effect of exercise intervention on flow-mediated dilatation (FMD) in overweight and obese adults. We searched four electronic databases (PubMed/Medline, Scopus, and CINAHL) through June 2016 for relevant studies pertaining to the effectiveness of exercise intervention on FMD. Seventeen of the 91 studies identified met the inclusion criteria. Comprehensive Meta-Analysis software (version 3) was used to compute the standardized mean difference effect size (ES) and 95% CI using a random effects model. We calculated 34 ESs. We found that exercise intervention had medium and positive effects on FMD, with an overall ES of 0.522 (95% CI = 0.257, 0.786). Heterogeneity of ESs was observed ( = 239, ≤ 0.001, 2 = 86.19), and the effect was moderated by comorbidity ( = 6.39, df = 1, = 0.011). A large ES for the combination exercise, low intensity exercise, and comorbidity subgroups (ES = 0.82∼1.24) was found. We conclude that while exercise intervention significantly improves FMD in overweight and obese adults, the effect may depend on the different characteristics of exercise intervention and on participants’ demographics

Optimal Frequency Intensity of Physical Activity to Reduce the Risk of Hypertension in the Korean Population

PURPOSE: Regular physical activity (PA) is an effective lifestyle modification for preventing hypertension. This study aimed to analyze the optimal frequency of PA required to reduce the incidence of hypertension in the Korean population. Most Korean studies have included only small samples and limited age ranges. METHODS: The present study analyzed 16,299,865 participants aged ≥20 years (44.25±12.74 years) from the 2009 to 2012 Korean National Health Insurance Corporation Survey database. The International Physical Activity Questionnaire was used to assess the frequency and intensity of physical activity. Hazard ratios for incident hypertension were analyzed by physical activity participation, age, and sex using multivariable Cox proportional hazard models, with a non-regular physical activity group as reference. RESULTS: A total of 1,322,674 cases of incident hypertension were identified during the mean follow-up period of over 3 years. Hazard ratios for incident hypertension increased with age, with values of 50.4 and 56.1 for men and women in the older age group, respectively. Hazard ratios for incident hypertension were significantly lower in the regular PA group of middle-aged (4%) and older (7%) adults than in the non-regular PA group. The study revealed that moderate-to-vigorous-intensity PA 3-5 times/week was most effective in reducing the risk of incident hypertension in middle-aged and older adults but not in young adults. We observed no additional lowering of incident hypertension risk in the group undergoing moderate-to-vigorous PA at a frequency of 6-7 days/week compared to the 35 days/week group. CONCLUSIONS: We suggest PA at a frequency of 3-5 times/week for the prevention of incident hypertension in Korean adults