Grass-Fed and Non-Grass-Fed Whey Protein Consumption Do Not Attenuate Exercise-Induced Muscle Damage and Soreness in Resistance-Trained Individuals: A Randomized, Placebo-Controlled Trial.

Eccentric muscle contractions can cause structural damage to muscle cells resulting in temporarily decreased muscle force production and soreness. Prior work indicates pasture-raised dairy products from grass-fed cows have greater anti-inflammatory and antioxidant properties compared to grain-fed counterparts. However, limited research has evaluated the utility of whey protein from pasture-raised, grass-fed cows to enhance recovery compared to whey protein from non-grass-fed cows. Therefore, using a randomized, placebo-controlled design, we compared the effect of whey protein from pasture-raised, grass-fed cows (PRWP) to conventional whey protein (CWP) supplementation on indirect markers of muscle damage in response to eccentric exercise-induced muscle damage (EIMD) in resistance-trained individuals. Thirty-nine subjects (PRWP, n = 14; CWP, n = 12) completed an eccentric squat protocol to induce EIMD with measurements performed at 24, 48, and 72 h of recovery. Dependent variables included: delayed onset muscle soreness (DOMS), urinary titin, maximal isometric voluntary contraction (MIVC), potentiated quadriceps twitch force, countermovement jump (CMJ), and barbell back squat velocity (BBSV). Between-condition comparisons did not reveal any significant differences (p ≤ 0.05) in markers of EIMD via DOMS, urinary titin, MIVC, potentiated quadriceps twitch force, CMJ, or BBSV. In conclusion, neither PRWP nor CWP attenuate indirect markers of muscle damage and soreness following eccentric exercise in resistance-trained individuals.

Differences in exercise-induced blood pressure changes between young trained and untrained individuals.

There are no studies assessing short-term blood pressure (BP) changes induced by daily exercise load in young trained individuals. The authors enrolled 25 healthy, trained (mean age 19.7 ± 0.1 years, 36% female) and 26 healthy, untrained (mean age 20.4 ± 0.3 years, 50% female) individuals and measured BP after the Master two-step test. Among them, 42 individuals underwent echocardiography after BP measurements to assess left ventricular mass index (LVMI). The baseline systolic BP (SBP) levels of trained and untrained individuals were 122.7 ± 2.9 versus 117.4 ± 1.5 mmHg, respectively (p = .016). Trained individuals showed a significant suppression of the SBP increase soon after exercise loads and lower SBP levels at 1, 2, and 3 min after exercise loads compared with untrained individuals. The peak SBP level over the study period was also significantly lower in trained individuals than in untrained individuals: 156.4 ± 3.3 versus 183.7 ± 5.2 mmHg (p < .001). Trained individuals showed significantly higher LVMI compared with untrained individuals: 129.4 versus 101.6 g/m2 (p < .001). These findings demonstrated that trained individuals showed significant suppression of short-term BP variability in response to by daily exercise loads and prompt SBP recovery from acute exercise loads compared with untrained individuals. Our results would be useful to understand short-term BPV and LV hypertrophy induced by adaptive responses of the heart to regular exercise loads.

Equal-Volume Strength Training With Different Training Frequencies Induces Similar Muscle Hypertrophy and Strength Improvement in Trained Participants.

The main goal of the current study was to compare the effects of volume-equated training frequency on gains in muscle mass and strength. In addition, we aimed to investigate whether the effect of training frequency was affected by the complexity, concerning the degrees of freedom, of an exercise. Participants were randomized to a moderate training frequency group (two weekly sessions) or high training frequency group (four weekly sessions). Twenty-one participants (male: 11, female: 10, age: 25.9 ± 4.0) completed the 9-week whole-body progressive heavy resistance training intervention with moderate (n = 13) or high (n = 8) training frequency. Whole-body and regional changes in lean mass were measured using dual-energy x-ray absorptiometry, while the vastus lateralis thickness was measured by ultrasound. Changes in muscle strength were measured as one repetition maximum for squat, hack squat, bench press, and chest press. No differences between groups were observed for any of the measures of muscle growth or muscle strength. Muscle strength increased to a greater extent in hack squat and chest press than squat and bench press for both moderate (50 and 21% vs. 19 and 14%, respectively) and high-frequency groups (63 and 31% vs. 19 and 16%, respectively), with no differences between groups. These results suggest that training frequency is less decisive when weekly training volume is equated. Further, familiarity with an exercise seems to be of greater importance for strength adaptations than the complexity of the exercise.

Effects of Intermittent Pneumatic Compression on Delayed Onset Muscle Soreness (DOMS) in Long Distance Runners.

The purpose of this study was to observe the effectiveness of intermittent pneumatic compression (IPC) on reducing C-reactive protein (CRP) and DOMS after long distance running. Ten distance runners, five males and five females, ages 20-53 years performed two 20-mile runs at 70% VO2 max. Each run was followed by either no treatment (control) or IPC treatment for five consecutive days. For the IPC run, participants were treated for one hour immediately following the run and daily for five more days thereafter. On control runs, participants did not receive any treatment. Serum CRP was measured pre- and post-run, and daily thereafter for five days for both trials. Results indicated no significant difference (p > 0.05) between control and treatment runs in CRP levels. Subjective pain ratings indicated no significant difference in pain between control and treatment runs. In conclusion, there appear to be no substantial benefits of IPC in promoting recovery.

Comparação do número máximo de repetições em séries múltiplas entre indivíduos com diferentes tempos de experiência no treinamento de força / Comparison of the maximum number of repetitions in multiple series between individuals with different times of experience in resistance training

O treinamento de força (TF) proporciona adaptações centrais e morfológicas que influenciam no processo de produção de força. Em função destas adaptações é esperado que ocorram diferenças no desempenho de força entre homens com diferentes tempos de experiência no TF quanto testados em séries múltiplas. Assim, este estudo teve como objetivo comparar o número máximo de repetições (NMR) realizadas em 3 séries entre indivíduos com diferentes tempos de experiência no TF. Para isso, vinte e dois homens foram divididos em dois grupos de acordo com o tempo de experiência no TF. O Grupo Muito Experiente (GME) foi representado por homens com mais de 5 anos no TF. O Grupo Pouco Experiente (GPE) foi composto por homens com 1 a 6 meses de experiência no TF. Os grupos foram submetidos à realização do maior número de repetições em três séries a 80% de 1RM no exercício supino reto. Além disso, a duração média da repetição (DMR) foi registrada e comparada em cada série intra e inter grupos. Para as comparações foram utilizadas duas ANOVAs com única variável (NMR ou DMR) e dois fatores (fator 1 = experiência, fator 2 = série). Na análise do NMR foi detectada uma interação entre os fatores, sendo que o número máximo de repetições realizado pelo GME foi maior do que o GPE apenas na primeira série (p = 0,017). Quanto à DMR, não foram encontradas diferenças entre os grupos (p = 0,80) e séries (p= 0,06). Conclui-se que o tempo de experiência no TF interferiu na realização do número máximo de repetições apenas na primeira série... (AU)

Strength training (TF) provides central and morphological adaptations that influence the process of force production. Due to these adaptations, it is expected that differences in force performance occurred between men with different times of experience in the TF when tested in multiple series. Thus, this study had as objective to compare the maximum number of repetitions (NMR) performed in 3 sets between individuals with different times of experience in the TF. For this, twenty-two men were split into two groups according to the time of experience in the TF. The Very Experienced Group (GME) was represented by men older with at least 5 years in TF. The Little Experienced Group (GPE) was composed of men with 1 to 6 months of experience in TF. The groups were submitted to perform the highest number of repetitions in three sets at 80% of 1RM in the bench press exercise. In addition, mean repetition duration (DMR) was recorded and compared in each set and group. For the comparison, two ANOVAs with a single variable (NMR or DMR) and two factors (factor 1 = experience, factor 2 = set) were used. In the NMR analysis, an interaction between the factors was detected, and the NMR performed by the GME was higher than the GPE only at the first set (p = 0.017). Regarding DMR, no differences were found between groups (p = 0.80) and sets (p = 0,06). It is concluded that the time of experience in the TF interfered in the Performance of the maximum number of repetitions only at the first set...(AU)

Cardiac remodeling after six weeks of high-intensity interval training to exhaustion in endurance-trained men.

High-intensity interval training (HIIT) improves physical performance of endurance athletes, although studies examining its cardiovascular effects are sparse. We evaluated the impact of HIIT on blood pressure, heart rate, and cardiac cavities' size and function in endurance-trained adults. Seventeen endurance-trained men underwent 24-h ambulatory blood pressure monitoring and Doppler echocardiography at baseline and after 6 wk of HIIT. Participants were divided into 2 groups [85% maximal aerobic power (HIIT85), n = 8 and 115% maximal aerobic power (HIIT115), n = 9] to compare the impact of different HIIT intensities. Ambulatory blood pressure monitoring and cardiac chambers' size and function were similar between groups at baseline. HIIT reduced heart rate (55 ± 8 vs. 51 ± 7 beats/min; P = 0.003), systolic blood pressure (121 ± 11 vs. 118 ± 9 mmHg; P = 0.01), mean arterial pressure (90 ± 8 vs. 89 ± 6 mmHg; P = 0.03), and pulse pressure (52 ± 6 vs. 49 ± 5 mmHg; P = 0.01) irrespective of training intensity. Left atrium volumes increased after HIIT (maximal: 50 ± 14 vs. 54 ± 14 mL; P = 0.02; minimal: 15 ± 5 vs. 20 ± 8 mL; P = 0.01) in both groups. Right ventricle global longitudinal strain lowered after training in the HIIT85 group only (20 ± 4 vs. 17 ± 3%, P = 0.04). In endurance-trained men, 6 wk of HIIT reduced systolic blood pressure and mean arterial pressure and increased left atrium volumes irrespective of training intensity, whereas submaximal HIIT deteriorated right ventricle systolic function.NEW & NOTEWORTHY The novel findings of this study are that 6 wk of high-intensity interval training increases left atrial volumes irrespective of training intensity (85 or 115% maximal aerobic power), whereas the submaximal training decreases right ventricular systolic function in endurance-trained men. These results may help identify the exercise threshold for potential toxicity of intense exercise training for at-risk individuals and ideal exercise training regimens conferring optimal cardiovascular protection and adapted endurance training for athletes.

Back pain in physically inactive students compared to physical education students with a high and average level of physical activity studying in Poland.

BACKGROUND: The aim of the study was (1) to characterise back pain in physically inactive students as well as in trained (with a high level of physical activity) and untrained (with an average level of physical activity) physical education (PE) students and (2) to find out whether there exist differences regarding the declared incidence of back pain (within the last 12 months) between physically inactive students and PE students as well as between trained (with a high level of physical activity) and untrained (with an average level of physical activity) PE students. METHODS: The study included 1321 1st-, 2nd- and 3rd-year students (full-time bachelor degree course) of Physical Education, Physiotherapy, Pedagogy as well as Tourism and Recreation from 4 universities in Poland. A questionnaire prepared by the authors was applied as a research tool. The 10-point Visual Analogue Scale (VAS) was used to assess pain intensity. Prior to the study, the reliability of the questionnaire was assessed by conducting it on the group of 20 participants twice with a shorter interval. No significant differences between the results obtained in the two surveys were revealed (p < 0.05). RESULTS: In the group of 1311 study participants, 927 (70.7%) respondents declared having experienced back pain within the last 12 months. Physically inactive students declared back pain frequency similar to the frequency declared by their counterparts studying physical education (p > 0.05). Back pain was more common in the group of trained students than among untrained individuals (p < 0.05). Back pain was mainly located in the lumbar spine. CONCLUSIONS: A frequent occurrence of back pain (70.7%) was noted in the examined groups of students. The percentage of students declaring back pain increased in the course of studies (p < 0.05) and, according to the students' declarations, it was located mainly in the lumbar spine. No significant differences regarding the incidence of back pain were found between physically inactive students and physical education students (p > 0.05). The trained students declared back pain more often than their untrained counterparts (p < 0.05).

Effect of 3-week high-intensity interval training on VO2max, total haemoglobin mass, plasma and blood volume in well-trained athletes.

PURPOSE: This study examined the haematological adaptations to high-intensity interval training (HIT), i.e. total haemoglobin mass (tHb-mass), blood volume (BV), and plasma volume (PV), and its effects on VO2max in well-trained athletes. METHODS: Twenty-seven male and eight female well-trained (VO2max 63.7 ± 7.7 ml/min/kg) athletes were randomly assigned to the HIT (HITG, N = 19) or the control group (CG, N = 16). Over a 3-week period, the HITG performed 11 HIT sessions, consisting of four 4-min interval bouts at an exercise intensity of 90-95 % of the individual maximal heart rate (HRmax), separated by 4-min active recovery periods. Before and 5 ± 2 days after the intervention, tHb-mass, BV and PV were determined by the CO-rebreathing method. VO2max was assessed in a laboratory treadmill test. RESULTS: tHb-mass (from 753 ± 124 to 760 ± 121 g), BV (from 5.6 ± 0.8 to 5.6 ± 0.9 l) and PV (from 3.2 ± 0.5 to 3.2 ± 0.5 l) remained unchanged after HIT and did not show an interaction (group × time). Within the HITG, VO2max improved from baseline by +3.5 % (p = 0.011), but remained unchanged in the CG. No interaction (group × time) was seen for VO2max. The HITG showed a significant reduction in HRmax compared to the baseline measurement (-2.3 %, p ≤ 0.001), but HRmax remained unchanged in the CG. There was a significant interaction (group × time) for HRmax (p = 0.006). Also, oxygen pulse significantly increased only in HITG from 22.9 ± 4.4 to 23.9 ± 4.2 ml/beat, with no interaction (p = 0.150). CONCLUSIONS: Eleven HIT sessions added to usual training did neither improve VO2max nor haematological parameters compared to the CG.