Effects of Dehydration on Resistance Training: An Ongoing Study

Introduction: Dehydration via hot bath has been shown to impair resistance training performance when performed the same day. The performance decrements in this instance could potentially be due to a combination of the dehydration and residual effects of the heat exposure and not of the dehydration alone. To date, no research has examined the effects of previous night dehydration on resistance training performance. Purpose: The purpose of this ongoing study was to determine the effects of previous night dehydration on performance and perceptual measures during a full-body resistance training protocol. Methods: Healthy, resistance trained males (n = 4) completed two bouts of a full body resistance training protocol (three sets to failure for bench press, lat pull, overhead press, bicep curl, triceps push down, and leg press), dehydrated (~3% body weight) (DT), or heat exposed with fluid replacement (HT). Heart rate (HR) was taken after every set, and participants estimated ratings of perceived exertion (RPE) after each exercise. Session RPE (SRPE) was estimated 5 minutes following completion of the protocol and estimations for feelings of recovery (PRS), perceived readiness to exercise (PR), thirst, and sleep quality. Results: Analysis revealed a significantly less (p = \u3c 0.001) total reps were completed for DT (163.0 ± 4.8) compared to HT (191.3 ± 10.3), though no differences were found for reps per exercise. No significant differences were found for HR (DT vs HT) at any time point. RPE was significantly higher for DT following bicep curl (p = 0.03) (DT: 7.8 ± 0.96, HT: 6.0 ± 0.82) and triceps push down (p = 0.03) (DT: 7.5 ± 0.58, HT: 6.0 ± 0.82). SRPE was significantly higher (p = 0.003) for DT (8.0 ± 0.0) vs HT (6.3 ± 0.5). Significant differences for PRS (p = 0.004) (DT: 5.0 ± 1.4, HT: 7.5 ± 0.58) and PR (p = \u3c 0.001) (DT: 5.0 ± 0.0, HT: 2.5 ± 0.58) indicate participants expected impaired performance during DT. Feelings of thirst were significantly higher (p = 0.001) for DT (7.98 ± 0.94) vs HT (2.73 ± 1.11). No differences were found for estimations of sleep quality (p = 0.59). Conclusion: Even though only preliminary data from a study presently ongoing, the present results suggest that previous night dehydration has a negative influence on both performance and perceptual measures

Effects of Hypohydration on Muscular Performance in Females: An Ongoing Study

Dehydration (~3%) has been shown to negatively affect anaerobic performance. A majority of this research has been conducted using male participants. Like males, females have been shown to underestimate sweat loss, which could lead to insufficient rehydration and thus hypohydration. Additionally, due to differences in thermoregulation, it is possible that females respond to hypohydration differently than males. To date, no research has examined the effects of previous night dehydration on muscular performance in females. PURPOSE: The purpose of this ongoing study was to determine the effects of previous night dehydration on muscular strength, muscular endurance, lower body power, and perceptual measures in resistance trained females. METHODS: Healthy, resistance trained females (n = 7) completed two bouts of resistance exercise, either dehydrated (~3% body weight) (DT) or heat exposed with fluid replacement (HT). Each exercise bout consisted of one rep maximum (1RM) for bench press followed by 5 sets to failure of 75% of 1RM, 1RM for leg press followed by 5 sets to failure of 75% of 1RM, and vertical jump assessment. Participants estimated ratings of perceived exertion (RPE) after each exercise. Session RPE (SRPE) was estimated 5 minutes following completion of the protocol and estimations for feelings of recovery (PRS), perceived readiness to exercise (PR), thirst, and sleep quality were estimated prior to workouts. RESULTS: Analysis revealed a bench press 1RM (p = 0.05) and leg press 1RM (p = 0.03) were significantly lower for DT (bench: 95.0 ± 34.0; leg press: 461.4 ± 141.7) compared to HT (bench: 97.9 ± 34.3; leg press: 500.0 ± 141.0). There was no difference in total reps completed for bench press (p = 0.32) or leg press (p = 0.37) for DT (bench press: 31.0 ± 6.7; leg press: 47.9 ± 21.6) compared to HT (bench press: 31.7 ± 5.0; leg press: 49.6 ± 22.8). There was no significant difference (p = 0.15) for vertical jump height (DT: 17.6 ± 2.2, HT: 18.1 ± 2.6). RPE was not significantly different following bench press (p = 0.5) (DT: 7.1 ± 1.1, HT: 7.1 ± 0.9) or leg press (p = 0.41) (DT: 6.7 ± 0.5, HT: 6.9 ± 1.7). SRPE was significantly higher (p = 0.05) for DT (6.6 ± 0.5) vs HT (5.9 ± 0.7). Significant differences for PRS (p = 0.03) (DT: 5.4 ± 2.2, HT: 7.05 ± 1.3) and PR (p = 0.01) (DT: 3.9 ± 0.9, HT: 2.6 ± 0.5) indicate participants expected impaired performance during DT. Feelings of thirst were significantly higher (p = 0.001) for DT (6.5 ± 2.5) vs HT (2.1 ± 2.3). Estimations of sleep quality were significantly lower (p = 0.05) for DT (4.3 ± 3.3) vs HT (7.2 ± 2.1). CONCLUSION: Even though only preliminary data from a presently ongoing study, the current results suggest that previous night dehydration has a negative influence on both performance and perceptual measures in resistance trained females

Body Composition Estimation and Satisfaction in College Students

College students are at an elevated risk for engaging in unhealthy lifestyle behaviors, including disordered eating and low levels of exercise. Evidence also suggests that college students inaccurately estimate their weight status (e.g., reporting they are overweight when they are at a normal weight) and report high levels of body dissatisfaction. Efforts to promote healthy behavior change and body satisfaction first require an accurate perception of the problem. The purpose of this study was to 1) determine the accuracy with which college students estimate their weight and body composition, and 2) better understand the relationship between body composition and body satisfaction. Methods: Forty-five college students (males = 21 and females = 24), between 18 and 30 years of age, completed a survey with items assessing demographic characteristics, weight status estimation, body composition estimation, and the Body Part Satisfaction Scale (BPSS). Body composition was assessed using Dual x-ray absorptiometry (DXA). Paired samples t-tests were used to compare means between participant’s objective measurements and their estimated measurements. Bivariate analyses were used to determine relationships between body part dissatisfaction and body composition. Results: Males and females accurately estimated their weight (d =-.16, SD = 2.56, t(44) = -.414, p = 0.68), but significantly underestimated their body fat percentage (d =-4.37, SD = 7.62, t(44) = -3.85), p = 0.001). Greater body dissatisfaction was associated with a higher body fat percentage (r =. 353), but not body fat percentage estimation (r = .164). In the trunk region, a higher body fat percentage in that region was significantly associated with greater dissatisfaction for abdomen size (r = .323); higher body fat percentage in the arms and legs were mildly associated with greater dissatisfaction in the respective areas (r = .268; r = .260), though not statistically significant. Conclusions: Although college students accurately estimated their weight, they significantly underestimated their fat mass, indicating a misunderstanding regarding the proportion of their body weight composed of fat tissue. As expected, greater fat mass in specific body parts (e.g., arms, legs, and truck) was related with greater dissatisfaction in those specific areas. Future research should continue to investigate these relationships and body composition estimation accuracy in more diverse samples. Health promotion initiatives should aim to educate students on body composition and continue to promote healthy behavior change along with body satisfaction

Restrictive Breathing Mask Reduces Total Repetitions in Resistance-Trained Males: An Ongoing Study

Recently a popular exercise training device has been developed, which has been promoted by companies as a training aid, known as a restrictive breathing mask (RBM).The RBM is designed to simulate training at higher altitudes and has become commonplace for individuals to utilize during resistance-training sessions. PURPOSE: The purpose of this study was to examine the impact of a RBM on muscle performance and perceptual measures in resistance-trained males. METHODS: A cross-over study design was utilized in 9 resistance-trained males with performance trials separated by 7 days. A baseline strength testing session was completed for 12RM for squat, leg press, and leg extension. Participants completed the lower body workout with no mask or RBM. After the initial warm up, participants completed 4 sets of reps to failure of squats, leg press, and leg extension with 2 minutes rest between sets and 3 minutes between exercises. Heart rate was collected immediately post set. Participants completed a 10cm visual stress scale immediately post resistance training session and Session RPE (SRPE) was collected 10 minutes post. Paired T-tests were utilized to analyze total session reps, SRPE, average post set session heart rate, and session stress scale. RESULTS: There was a significant reduction in total session reps during the RBM trial compared to the no mask trial (p\u3c 0.001). SRPE was significantly higher during the RBM trial compared to the no mask trial (p= 0.003). There was a significant elevation in perceived stress during the RBM trial (p= 0.01). Finally, there was a statistically significant increase in post set heart rate during the RBM session (p=0.04) CONCLUSION: Based on the performance variables, it appears that a RBM reduces the total repetitions that an individual can complete during an acute bout of resistance training, while also increasing the perceived difficulty and stressfulness of the bout. Subsequently, a reduction in mechanical stimuli could result in a diminished hypertrophic response over time

The Effects of Short-Term Detraining and Subsequent Retraining on Body Composition and Muscle Performance in Males Consuming a Whey Protein or Carbohydrate Supplement

An acute bout of resistance exercise (RE) can up-regulate processes that stimulate muscle protein synthesis (MPS). Additionally, nutritional strategies involving carbohydrate (CHO) and whey protein (WP) supplementation can augment MPS. However, resistance training (RT) induced muscle anabolism during the early phases of training can attenuate over time. The use of a short-term cessation of training (detraining; DT) can potentially restore the attenuated muscular anabolic adaptive responses. Therefore, the purpose of this study was to explore the effects of a successive cycle of detraining and retraining (ReT) in humans on body composition and muscle performance. Resistance-trained males (age 20.95 ± 1.23 y; n=20) were recruited and randomized into one of two groups (WP or CHO; 25 grams) in a double-blind fashion. Both groups followed a standardized 4 days per week resistance-training program for 4 weeks, carried out 2 weeks of DT and continued the resistance-training program for another 4 weeks of ReT. Participants were instructed to consume their respective supplement only on workout days during RT, but every day during DT. Research visits were conducted at baseline, 4 weeks (post-RT), 6 weeks (post-2-week-DT), and after 10 weeks (post-ReT). Each visit consisted of body composition assessments and muscular strength and endurance testing using the bench press and angled leg press exercises. Four-day diet records, workout logs, and supplement compliance forms were utilized. Factorial 2x4 (group by time) ANOVAs with repeated measures were conducted using SPSS (version 20.0) with a probability level of ≤ .05. There were no significant group by time interactions for lean or fat mass changes throughout the study (p \u3e .05). However, both groups were able to retain lean mass following 2 weeks of DT. The WP group appeared to have an elevation in lean mass (+1.58kg on average) by the end of ReT in comparison to baseline, even though it was not statistically significant (p \u3e .05). Leg press strength (LPS) increased throughout the study (p=.003), and neither group showed a decrease in LPS following DT. There were no group-by-time interactions or group differences between WP and CHO for bench press strength (BPS), bench press endurance (BPE), leg press endurance (LPE), or any dietary variables (p \u3e .05). Interestingly, the WP group presented a non-significant overall increase in lean mass compared to the CHO group by the end of 10 weeks. LPS and BPS were also elevated and retained respectfully following DT. In summary, a short-term 2 week cycle of DT in resistance trained males maintained both muscle mass and muscular strength, which potentially reinforces the importance of recovery

Effects of Fish Oil Supplementation on Post-Resistance Exercise Muscle Soreness in Untrained Females

The anti-inflammatory properties of omega-3 fatty acids contained in fish oil may help alleviate symptoms of delayed onset of muscle soreness (DOMS) and improve recovery from exercise. PURPOSE: To examine the effects of fish oil supplementation on the time-course of post-resistance exercise muscle soreness in young untrained females. METHODS: Seventeen non-resistance trained females (age 23.6 ± 3.0 y, % fat 27.4 ± 3.2, weight 60.2 ± 9.6 kg) were randomized into one of two groups: fish oil (6 g/d; 5:1 EPA:DHA) or placebo (6 g/d corn/soy oil). After consuming the supplements for one week, participants underwent a single bout of resistance exercise designed to induce muscle damage. Subjects performed 10 sets to failure of biceps curl machine and leg extensions using 50% of the previously measured 1-repetition maximum. Over the next week, subjective muscle soreness of the upper and lower body was measured via a grounded 10-cm visual analog scale. At 48 hours and 1 week post-exercise, subjects performed a test to determine soreness during functional movements. The comparison-wise error rate was set at p \u3c 0.10. RESULTS: Muscle soreness increased significantly in both groups and peaked at 48 hours post-exercise. The fish oil group perceived less muscle soreness in the lower body than the placebo group (p= 0.06), but there was no difference in the upper body (p= 0.27). The fish oil group reported less perceived soreness during functional movements (p= 0.07 for upper and lower body soreness). Effect sizes, indicating the reduction in muscle soreness that may be attributed to fish oil (Δ effect size between groups), was 0.75 (95% CI: -0.70 – 2.20) for the arms and 0.77 (-0.76 – 2.33) for the legs. The effect size for the functional tests was 0.63 (-0.71 – 1.97) for the arms and 0.57 (-0.85 – 1.99) for the legs. CONCLUSION: Supplementing the diet with 6 grams per day of fish oil may alleviate the muscle soreness experienced after resistance training in young untrained females, but additional studies with larger sample sizes should be conducted to confirm these findings

Effect of Resistance Exercise Intensity on the mRNA Expression of PGC-1α Isoforms in Human Skeletal Muscle

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A Student\u27s Guide to giant Viruses Infecting Small Eukaryotes: From Acanthamoeba to Zooxanthellae

The discovery of infectious particles that challenge conventional thoughts concerning “what is a virus” has led to the evolution a new field of study in the past decade. Here, we review knowledge and information concerning “giant viruses”, with a focus not only on some of the best studied systems, but also provide an effort to illuminate systems yet to be better resolved. We conclude by demonstrating that there is an abundance of new host–virus systems that fall into this “giant” category, demonstrating that this field of inquiry presents great opportunities for future research

The effects of hypohydration on muscular performance and markers of catabolism in females.

The purpose of this study was to determine the effects of previous night dehydration on muscular strength, endurance, and lower-body power, perceptual measures, and markers of catabolism in resistance-trained females. Ten healthy, resistance-trained females completed two bouts of resistance exercise, either dehydrated (~3% body weight) (DT) or heat exposed with fluid replacement (HT). Each exercise bout consisted of one rep maximum (1RM) followed by five sets to failure of 75% of 1RM for bench press and leg press, and vertical jump assessment. Muscle and blood samples were obtained prior to and 1hr following exercise. Blood samples were obtained to examine cortisol. From each muscle sample, glucocorticoid receptor-DNA (GR-DNA) binding and mRNA expression were determined. Bench press 1RM (p = 0.04) was significantly lower for DT compared to HT. No significant difference was found for leg press 1RM. There was no difference in total reps completed for bench press or leg press. No significant differences were found for total volume lifted for bench press or leg press or vertical jump. There were no significant interactions between session and time for any markers of mRNA expression. There was no significant interaction or main effects for session and time for serum cortisol. There was a significant main effect for session for GR- DNA binding (p = 043). GR-DNA binding was significantly elevated post exercise for DT (p = .016). Current results suggest that hypohydration may have a negative impact on bench press 1RM performance. Though the only performance measure to reach a statistically significant difference was bench press 1RM, there was a reduction in leg press 1RM and total volume lifted for both bench press and leg press. While this was an acute bout of only two exercises, it would be reasonable to suggest that this reduction in volume would continue for other exercises across a full workout. Additionally, GR-DNA binding was increased with hypohydration. Theoretically, if an individual were to be chronically hypohydrated, this reduction in volume and increase in GR-DNA binding could diminish the anabolic response to resistance exercise and potentially lead to muscle atrophy