Electromyographical Comparison of a Traditional, Suspension Device, and Towel Pull-Up

Strengthening muscles of the back may have various implications for improving functions of daily living, aiding in the transfer of power in throwing, and assist in injury prevention of the shoulder complex. While several versions of the pull-up exist, there is currently no literature comparing their differences. The purpose of this investigation was to compare the electromyographical activity of the latissimus dorsi, posterior deltoid, middle trapezius, and biceps brachii while performing three variations of the pull-up. Resistance-trained men and women (n = 15, age = 24.87 ± 6.52 years) participated in this study by performing traditional pull-ups, suspension device pull-ups, and towel pull-ups in a randomized fashion. Each pull-up was performed for three repetitions with a 1.5 bi-acromial grip-width for each participant. Normalized (%MVC) electromyographical values were recorded for each muscle group during each pull-up variation. No significant differences existed within the latissimus dorsi, biceps brachii or posterior deltoid between any of the exercises. For the middle trapezius, towel pull-ups provided significantly lower muscle activity than the traditional pull-up, while no differences between suspension pull-ups and the other variations occurred. In conclusion, only one muscular difference existed between the exercise variations and all versions examined provided electromyographical values, determined by current literature, to invoke a sufficient stimulus to promote increases in muscle strength and hypertrophy. Although further research is needed, practitioners can be confident when programming any of the movement variations examined when attempting to elicit adaptations of muscular strength and hypertrophy

Daily Heart Rate Variability before and after Concussion in an American College Football Player

This case report demonstrates the effects of sport-related concussion (SRC) on heart rate variability (HRV) in an American college football player. Daily measures of resting, ultra-short natural logarithm of the root mean square of successive differences (LnRMSSD), subjective wellbeing, and Player Load were obtained each training day throughout a 4-week spring camp and 4 weeks of preseason training. SRC occurred within the first 2 weeks of the preseason. During spring camp and preseason pre-SRC, the athlete demonstrated minimal day-to-day fluctuations in LnRMSSD, which increased post-SRC (LnRMSSD coefficient of variation pre-SRC ≤ 3.1%, post-SRC = 5.8%). Moderate decrements in daily-averaged LnRMSSD were observed post-SRC relative to pre-SRC (Effect Size ± 90% Confidence Interval = −1.12 ± 0.80), and the 7-day rolling average fell below the smallest worthwhile change for the remainder of the preseason. LnRMSSD responses to SRC appeared similar to trends associated with stress and training fatigue. Therefore, performance and sports medicine staff should maintain regular communication regarding player injury and fatigue status so that HRV can be interpreted in the appropriate context. Detection and monitoring of autonomic dysregulation post-SRC may require near-daily assessment, as LnRMSSD showed greater daily fluctuations rather than chronic suppression following the head injury

Validity of smartphone heart rate variability pre- and post-resistance exercise

The aim was to examine the validity of heart rate variability (HRV) measurements from photoplethysmography (PPG) via a smartphone application pre- and post-resistance exercise (RE) and to examine the intraday and interday reliability of the smartphone PPG method. Thirty-one adults underwent two simultaneous ultrashort-term electrocardiograph (ECG) and PPG measurements followed by 1-repetition maximum testing for back squats, bench presses, and bent-over rows. The participants then performed RE, where simultaneous ultrashort-term ECG and PPG measurements were taken: two pre- and one post-exercise. The natural logarithm of the root mean square of successive normal-to-normal (R-R) differences (LnRMSSD) values were compared with paired-sampl

Relationships between Workload, Heart Rate Variability, and Performance in a Recreational Endurance Runner

[EN] Background: The association between heart rate variability (HRV), training load (TL), and performance is poorly understood. Methods: A middle-aged recreational female runner was monitored during a competitive 20-wk macrocycle divided into first (M1) and second mesocycle (M2) in which best performances over 10 km and 21 km were recorded. Volume (km), session rating of perceived exertion (sRPE), TL, and monotony (mean TL/SD TL) were the workload parameters recorded. The root mean square of the successive differences in R-R intervals (RMSSD), its coefficient of variation (RMSSDcv), and the RMSSD:RR ratio were the HRV parameters monitored. Results: During M2, RMSSD (p = 0.006) and RMSSD:RR (p = 0.002) were significantly increased, while RR was significantly reduced (p = 0.017). Significant correlations were identified between monotony and volume (r = 0.552; p = 0.012), RR (r = 0.447; p = 0.048), and RMSSD:RR (r = −0.458; p = 0.042). A sudden reduction in RMSSD (from 40.31 to 24.34 ms) was observed the day before the first symptoms of an influenza. Conclusions: The current results confirm the practicality of concurrent HRV and sRPE monitoring in recreational runners, with the RMSSD:RR ratio indicative of specific adaptations. Excessive training volume may be associated to both elevated monotony and reduced RMSSD:RR. Identification of mesocycle patterns is recommended for better individualization of the periodization use

Acute Blood Flow Responses to Varying Blood Flow Restriction Pressures in the Lower Limbs

International Journal of Exercise Science 16(2): 118-128, 2023. The purpose of this study was to investigate lower limb blood flow responses under varying blood flow restriction (BFR) pressures based on individualized limb occlusion pressures (LOP) using a commonly used occlusion device. Twenty-nine participants (65.5% female, 23.8 ± 4.7 years) volunteered for this study. An 11.5cm tourniquet was placed around participants’ right proximal thigh, followed by an automated LOP measurement (207.1 ± 29.4mmHg). Doppler ultrasound was used to assess posterior tibial artery blood flow at rest, followed by 10% increments of LOP (10-90% LOP) in a randomized order. All data were collected during a single 90-minute laboratory visit. Friedman’s and one-way repeated-measures ANOVAs were used to examine potential differences in vessel diameter, volumetric blood flow (VolFlow), and reduction in VolFlow relative to rest (%Rel) between relative pressures. No differences in vessel diameter were observed between rest and all relative pressures (all p \u3c .05). Significant reductions from rest in VolFlow and %Rel were first observed at 50% LOP and 40% LOP, respectively. VolFlow at 80% LOP, a commonly used occlusion pressure in the legs, was not significantly different from 60% (p = .88), 70% (p = .20), or 90% (p = 1.00) LOP. Findings indicate a minimal threshold pressure of 50%LOP may be required to elicit a significant decrease in arterial blood flow at rest when utilizing the 11.5cm Delfi PTSII tourniquet system

Effects of Heat Exposure on Body Water Assessed using Single-Frequency Bioelectrical Impedance Analysis and Bioimpedance Spectroscopy

International Journal of Exercise Science 10(7): 1085-1093, 2017. The purpose of this study was to determine if heat exposure alters the measures of total body water (TBW), extracellular water (ECW), and intracellular water (ICW) in both single-frequency bioelectrical impedance analysis (BIA) and bioimpedance spectroscopy (BIS). Additionally, we sought to determine if any differences exist between the BIA and BIS techniques before and after brief exposure to heat. Body water was evaluated for twenty men (age=24±4 years) in a thermoneutral environment (22°C) before (PRE) and immediately after (POST) 15 min of passive heating (35°C) in an environmental chamber. The mean difference and 95% limits of agreement at PRE demonstrated that BIS yielded significantly higher body water values than BIA (all p0.05; 0.2±1.5kg). Additionally, the ES of the mean differences at POST were trivial to small and the r-values were high (r≥0.96). When analyzing the changes in body water before and after heat exposure, POST values for BIS were significantly higher than PRE (all

Cardiovascular autonomic modulation following maximal exercise: Its relationship to race, maximal oxygen uptake, and resting heart rate variability

The purpose of this dissertation was to provide a better understanding of post maximal exercise cardiovascular autonomic function and its relationship to race, VO2max and resting heart rate variability. Heart rate variability (HRV) and heart rate recovery (HRR) are two non-invasive methods to assess cardiovascular autonomic modulation. This dissertation covers three studies. The first study examined the difference in cardiac autonomic function at rest and following maximal exercise between 30 white and 30 black college-age men. The results showed that black men had significantly greater HRV measures at rest, significantly faster heart rate recovery 2-minutes after exercise and significantly greater HRV during a 30-minute post-exercise period compared to the white men. The second study sought to determine the association of race, VO2max, and selected body composition measures to HRR. In this study, seventy-two college-aged men were divided into two groups above and below the mean VO2max of the entire sample (46.32 ml/kg/min) as follows: group 1 (ModFit, n = 36) had a mean VO2max of 39.99 ± 4.01 ml/kg/min; and Group 2 (HiFit, n = 36) had a mean VO2max of 52.66 ± 5.30 ml/kg/min. After comparing the mean heart rate recovery between the two groups, no significant difference was found. However, after controlling for the influence of race, a significant difference between groups in heart rate recovery 2-minutes (HRR2) was revealed, i.e., the HiFit group had a greater HRR2 compared to the LoFit group. Also, backwards linear regression procedures revealed that race was the most significant variable at accounting for the variation in HRR2 and the heart rate at 2-minutes post-exercise. The third study examined the relationship between resting HRV and HRR. The results of this study revealed no association between HRR and any of the resting HRV. However, there were significant associations between resting HRV and the following variables: maximal heart rate, heart rate at 1-minute post-exercise, and the heart rate a 2-minutes post-exercise

Cardiac-autonomic Responses to in-season Training Among Division-1 College Football Players

Presentation given at American College of Sports Medicine Southeast Conference. Program PURPOSE: To determine if recovery of vagally-mediated heart rate variability (HRV) to resting values occurs between consecutive-day, in-season training sessions among college football players. METHODS: Subjects (n = 29) were divided into groups based on position as follows: receivers and defensive backs (SKILL, n = 10); running backs, linebackers and tight-ends (MID-SKILL, n = 11) and linemen (LINEMEN, n = 8). The natural logarithm of the root-mean square of successive differences multiplied by twenty (LnRMSSD) was acquired at rest in the seated position prior to Tuesday and Wednesday training sessions. Data collection procedures were repeated over three weeks during the first month of the competitive season. RESULTS: A position × time interaction was observed for LnRMSSD (p = 0.04). Between-day differences in LnRMSSD were trivial and non-significant for SKILL (Tuesday = 82.8 ± 9.3, Wednesday = 81.9 ± 8.7, p \u3e 0.05). Small and significant reductions in LnRMSSD between days were observed for MID-SKILL (Tuesday = 79.2 ± 9.4, Wednesday = 76.2 ± 9.5, p \u3c 0.05) and LINEMEN (Tuesday = 79.4 ± 10.5, Wednesday = 74.5 ± 11.5, p \u3c 0.05). The individual changes in LnRMSSD from Tuesday to Wednesday were significantly related to external training load (r = 0.46, p = 0.02) and body mass (r = - 0.39, p = 0.04). CONCLUSIONS: Cardiac-parasympathetic activity did not return to resting values for LINEMEN or MID-SKILL prior to the next training session. Larger reductions in LnRMSSD tended to occur in players with greater body mass and lower workloads, though some individual variability was observed