Single Bout Of Resistance Exercise Research Articles

Acute resistance exercise and pressure pain sensitivity in knee osteoarthritis: a randomised crossover trial

To determine whether a single bout of resistance exercise produces an analgesic effect in individuals with knee osteoarthritis (OA). Eleven participants with knee OA (65.9 ± 10.4 yrs), and 11 old (61.3 ± 8.2 yrs) and 11 young (25.0 ± 4.9 yrs) healthy adults performed separate bouts of upper and lower body resistance exercise. Baseline and post-exercise pressure pain thresholds were measured at eight sites across the body and pressure pain tolerance was measured at the knee. Pressure pain thresholds increased following exercise for all three groups, indicating reduced pain sensitivity. For the young and old healthy groups this exercise-induced analgesia (EIA) occurred following upper or lower body resistance exercise. In contrast, only upper body exercise significantly raised pain thresholds in the knee OA group, with variable non-significant effects following lower body exercise. Pressure pain tolerance was unchanged in all groups following either upper or lower body exercise. An acute bout of upper or lower body exercise evoked a systemic decrease in pain sensitivity in healthy individuals irrespective of age. The decreased pain sensitivity following resistance exercise can be attributed to changes in pain thresholds, not pain tolerance. While individuals with knee OA experienced EIA, a systemic decrease in pain sensitivity was only evident following upper body exercise.

Periexercise coingestion of branched-chain amino acids and carbohydrate in men does not preferentially augment resistance exercise–induced increases in phosphatidylinositol 3 kinase/protein kinase B–mammalian target of rapamycin pathway markers indicative of muscle protein synthesis

The effects of a single bout of resistance exercise (RE) in conjunction with periexercise branched-chain amino acid (BCAA) and carbohydrate (CHO) ingestion on skeletal muscle signaling markers indicative of muscle protein synthesis were determined. It was hypothesized that CHO + BCAA would elicit a more profound effect on these signaling markers compared with CHO. Twenty-seven males were randomly assigned to CHO, CHO + BCAA, or placebo (PLC) groups. Four sets of leg presses and leg extensions were performed at 80% 1 repetition maximum. Supplements were ingested 30 minutes and immediately before and after RE. Venous blood and muscle biopsy samples were obtained immediately before supplement ingestion and 0.5, 2, and 6 hours after RE. Serum insulin and glucose and phosphorylated levels of muscle insulin receptor substrate 1 (IRS-1), protein kinase B, mammalian target of rapamycin, phosphorylated 70S6 kinase, and 4E binding protein 1 were assessed. Data were analyzed by 2-way repeated-measures analysis of variance. Significant group × time interactions were observed for glucose and insulin (P < .05) showing that CHO and CHO + BCAA were significantly greater than PLC. Significant time main effects were observed for IRS-1 (P = .001), protein kinase B (P = .031), mammalian target of rapamycin (P = .003), and phosphorylated 70S6 kinase (P = .001). Carbohydrate and CHO + BCAA supplementation significantly increased IRS-1 compared with PLC (P = .002). However, periexercise coingestion of CHO and BCAA did not augment RE-induced increases in skeletal muscle signaling markers indicative of muscle protein synthesis when compared with CHO.

Effects of a Single Low-Intensity Resistance Exercise Session on Lipid Peroxidation of Untrained Male Students

Introduction: The aim of the present study was to examine the effects of a single bout of resistance exercise with low intensity of oxidative stress on male students who did not do any regular sports whatsoever. Materials and Methods: For this purpose, 16 untrained subjects with a mean age of 24.40 ± 1.7 years, height 176 ± 6.83 cm, weight 69.89 ± 6.6 and BMI 22.89 ± 0.89 kg/ m2, were studied pre and post a low intensity resistance exercise. The exercise protocol involved Scott and leg stretching for the lower limbs and stretch underarm and chest press for the upper limbs. The subjects performed each exercise 3 times (one minute rest between sets). The low- intensity test was performed in 25-30% of one repetition maximum (25 to 30 reps). Malondialdehyde (MDA) as an index of lipid peroxidation was measured before exercise, immediately after and 6 and 24 h after exercise. Results: Our data were analyzed using one factor repeated measures. Our results revealed a significant increase in MDA in response to low intensity resistance exercise at pre and post exercise time points in untrained subjects (P<0.05). The peak increase was observed at immediately post-exercise time point (P<0.0001, F=98.36) and the measures returned to resting values 24 hours after the test. Conclusion: Overall, resistance exercise, even though low-intense one appears to increase resistance oxidative stress.

Ageing has no effect on the regulation of the ubiquitin proteasome-related genes and proteins following resistance exercise

Skeletal muscle atrophy is a critical component of the ageing process. Age-related muscle wasting is due to disrupted muscle protein turnover, a process mediated in part by the ubiquitin proteasome pathway (UPP). Additionally, older subjects have been observed to have an attenuated anabolic response, at both the molecular and physiological levels, following a single-bout of resistance exercise (RE). We investigated the expression levels of the UPP-related genes and proteins involved in muscle protein degradation in 10 older (60–75 years) vs. 10 younger (18–30 years) healthy male subjects at basal as well as 2 h after a single-bout of RE. MURF1, atrogin-1 and FBXO40, their substrate targets PKM2, myogenin, MYOD, MHC and EIF3F as well as MURF1 and atrogin-1 transcriptional regulators FOXO1 and FOXO3 gene and/or protein expression levels were measured via real time PCR and western blotting, respectively. At basal, no age-related difference was observed in the gene/protein levels of atrogin-1, MURF1, myogenin, MYOD and FOXO1/3. However, a decrease in FBXO40 mRNA and protein levels was observed in older subjects, while PKM2 protein was increased. In response to RE, MURF1, atrogin-1 and FBXO40 mRNA were upregulated in both the younger and older subjects, with changes observed in protein levels. In conclusion, UPP-related gene/protein expression is comparably regulated in healthy young and old male subjects at basal and following RE. These findings suggest that UPP signaling plays a limited role in the process of age-related muscle wasting. Future studies are required to investigate additional proteolytic mechanisms in conjunction with skeletal muscle protein breakdown (MPB) measurements following RE in older vs. younger subjects.

Are skeletal muscle FNDC5 gene expression and irisin release regulated by exercise and related to health?

Recently, contradictory findings have been reported concerning the function of irisin and its precursor gene, skeletal muscle FNDC5, in energy homeostasis, and the associated regulatory role of exercise and PGC-1α. We therefore evaluated whether muscle FNDC5 mRNA and serum irisin are exercise responsive and whether PGC-1α expression is associated with FNDC5 expression. The male subjects in the study performed single exercises: (1) 1 h low-intensity aerobic exercise (AE) (middle-aged, n = 17), (2) a heavy-intensity resistance exercise (RE) bout (young n = 10, older n = 11) (27 vs. 62 years), (3) long-term 21 weeks endurance exercise (EE) training alone (twice a week, middle-aged, n = 9), or (4) combined EE and RE training (both twice a week, middle-aged, n = 9). Skeletal muscle mRNA expression was analysed by quantitative PCR and serum irisin by ELISA. No significant changes were observed in skeletal muscle PGC-1α, FNDC5 and serum irisin after AE, EE training or combined EE + RE training. However, a single RE bout increased PGC-1α by 4-fold in young and by 2-fold in older men, while FNDC5 mRNA only increased in young men post-RE, by 1.4-fold. Changes in PGC-1α or serum irisin were not consistently accompanied by changes in FNDC5. In conclusion, for the most part, neither longer-term nor single exercise markedly increases skeletal muscle FNDC5 expression or serum irisin. Therefore their changes in response to exercise are probably random and not consistent excluding the confirmation of any definitive link between exercise and FNDC5 expression and irisin release in humans. Moreover, irisin and FNDC5 were not associated with glucose tolerance and being overweight, or with metabolic disturbances, respectively. Finally, factor(s) other than PGC-1α and transcription may regulate FNDC5 expression.

Refining dietary protein recommendations for the athlete

Refining dietary protein recommendations for the athlete

Low-intensity resistance exercise does not affect cardiac autonomic modulation in patients with peripheral artery disease

OBJECTIVE:To analyze the effect of a single bout of resistance exercise on cardiac autonomic modulation in patients with peripheral artery disease.METHODS:Fifteen patients with peripheral artery disease (age: 58.3±4.0 years) underwent the following sessions in a random order: resistance exercise (three sets of 10 repetitions of the six resistance exercises with a workload of 5–7 in the OMNI-RES scale) and control (similar to the resistance session; however, the resistance exercises were performed with no load). The frequency domain (low frequency, high frequency and sympathovagal balance) and symbolic analysis (0V, 1V and 2V patterns) of heart rate variability were obtained before and until one hour after the interventions.RESULTS:After the resistance exercise and control sessions, similar increases were observed in the consecutive heartbeat intervals (control: 720.8±28.6 vs. 790.9±34.4 ms; resistance exercise: 712.9±30.1 vs. 756.8±37.9 ms; p<0.05) and in the pattern of the symbolic analysis with no variation (0V) (control: 25.1±3.5 vs. 33.4±4.1%; resistance exercise: 26.1±3.2 vs. 29.7±3.5%; p<0.05) until 50 min after both interventions. The pattern of two variations (2V) decreased similarly (control: 11.2±2.1 vs. 8.3±2.1%; resistance exercise: 9.5±1.7 vs. 7.8±1.7%; p<0.05). In contrast, the pattern of one variation (1V), the low and high frequency bands and sympathovagal balance did not change after the interventions (p>0.05).CONCLUSION:A single bout of resistance exercise did not alter cardiac autonomic modulation in patients with peripheral artery disease.

Fos expression on medullary and hypothalamic areas after resistance exercise in rats.

The acute effects of exercise are generated by alterations in the autonomic nervous system that is mediated through the integration of multiple nuclei of autonomic control. The aim of this study was to evaluate the Fos protein expression on the hypothalamic and medullary areas of cardiovascular control after a single bout of resistance exercise (RE). Were used Wistar rats (250g–300g) divided into two groups: sham (SH) and resistance exercise (RE). The animals performed the RE protocol (10 sets of 10 repetitions with 2 min for recovery) in a squat apparatus with 60% of 1RM. The animals were anesthetized, perfused, the brain was removed and sliced in a cryostat for immunohistochemistry method. The brain sections were subjected to immunofluorescence protocol. Fos protein immunoreactivity increase when compared to SH in the nucleus tractus solitary (RE = 15.3 ± 0.6 vs. SH = 1.6 ± 0.6), in the caudal ventrolateral region of the medulla (RE = 23.3 ± 0.8 vs SH 1.3 ± 0.3) and in the paraventricular nucleus of the hypothalamus (RE = 59.3 ± 4.2 vs SH 1.3 ± 0.3), we showed that after RE there is an intense activation of important brain areas for cardiovascular control during the post exercise period. Suggesting mobilization and possible interaction of specifics nuclei of brain to correct homeostatic changes produced by RE. Research support: CAPES, Fapitec.

Regulation of the STARS signaling pathway in response to endurance and resistance exercise and training

The striated muscle activator of Rho signaling (STARS) protein and members of its downstream signaling pathway, including myocardin-related transcription factor-A (MRTF-A) and SRF, are increased in response to prolonged resistance exercise training but also following a single bout of endurance cycling. The aim of the present study was to measure and compare the regulation of STARS, MRTF-A and SRF mRNA and protein following 10 weeks of endurance training (ET) versus resistance training (RT), as well as before and following a single bout of endurance (EE) versus resistance exercise (RE). Following prolonged training, STARS, MRTF-A and SRF mRNA levels were all increased by similar magnitude, irrespective of training type. In the training-habituated state, STARS mRNA increased following a single-bout RE when measured 2.5 and 5 h post-exercise and had returned to resting level by 22 h following exercise. MRTF-A and SRF mRNA levels were decreased by 2.5, 5, and 22 h following a single bout of RE and EE exercise when compared to their respective basal levels, with no significant difference seen between the groups at any of the time points. No changes in protein levels were observed following the two modes of exercise training or a single bout of exercise. This study demonstrates that the stress signals elicited by ET and RT result in a comparable regulation of members of the STARS pathway. In contrast, a single bout of EE and RE, performed in the trained state, elicit different responses. These observations suggest that in the trained state, the acute regulation of the STARS pathway following EE or RE may be responsible for exercise-specific muscle adaptations.

Effects of acute resistance exercise on cognition in late middle-aged adults: General or specific cognitive improvement?

To evaluate the effect of acute resistance exercise on multiple cognitive measures in late middle-aged adults and to address the question of whether general or selective cognitive improvements occur. A counterbalanced repeated-measures experimental design. Thirty adults (mean age=58.1 ± 3.0 years) were administered five different Stroop test conditions before and after a single bout of resistance exercise and after a no-treatment control. The resistance exercise protocol involved two sets of seven exercises performed at 70% of a 10-repetition maximum, with 30 and 60 s between each set and each exercise, respectively. The exercise treatment resulted in significantly enhanced performance across all Stroop conditions when compared with the control (p<.001). Furthermore, the effect of the exercise treatment on Stroop incongruent performance corresponded to the largest positive influence compared to the performance observed under the other four Stroop test conditions. These findings extend the current knowledge base by demonstrating that acute resistance exercise facilitates general cognition but has a more beneficial effect on cognition that involves executive control.

A Bout of Resistance Exercise Following the 2007 AHA Guidelines Decreases Asleep Blood Pressure in Mozambican Men

Hypertension is highly prevalent among African individuals and descendants, and in this ethnic group, asleep blood pressure is strongly associated with target organ damage. After its execution, a single bout of resistance exercise may decrease blood pressure in white individuals, but its effects are unknown in Africans. This study investigated the effects of a bout of resistance exercise, conducted in accordance with the 2007 American Heart Association (AHA) guidelines, on postexercise blood pressure in African subjects. Twenty-four Mozambican men (40 ± 2 years) underwent, in a random order, 2 experimental sessions: control (sitting resting) and exercise [8 resistance exercises, 1 set, 10-15 repetitions, 30-40% of 1 repetition maximum (1RM) for upper-body muscles and 50-60% of 1RM for lower-body muscles]. Before and after the interventions, clinic blood pressure was measured. Ambulatory blood pressure was also evaluated after both sessions. Clinic systolic blood pressure did not change after both interventions, whereas diastolic blood pressure increased significantly and similarly after the control and the exercise sessions. Twenty-four-hour (127 ± 3 mm Hg vs. 130 ± 3 mm Hg and 78 ± 2 mm Hg vs. 81 ± 2 mm Hg, respectively, p < 0.05) and asleep (119 ± 4 mm Hg vs. 123 ± 4 mm Hg and 69 ± 3 mm Hg vs. 72 ± 3 mm Hg, respectively, p < 0.05) systolic and diastolic blood pressures were lower after the exercise than in the control session. These results show that in African men, a single bout of resistance exercise, conducted in accordance with 2007 AHA guidelines, decreased 24-hour and asleep blood pressures. These reductions might represent an important benefit for African individuals and descendants among whom target organ damage is mainly associated with ambulatory blood pressure levels.

Early Activation of Rat Skeletal Muscle IL-6/STAT1/STAT3 Dependent Gene Expression in Resistance Exercise Linked to Hypertrophy

Cytokine interleukin-6 (IL-6) is an essential regulator of satellite cell-mediated hypertrophic muscle growth through the transcription factor signal transducer and activator of transcription 3 (STAT3). The importance of this pathway linked to the modulation of myogenic regulatory factors expression in rat skeletal muscle undergoing hypertrophy following resistance exercise, has not been investigated. In this study, the phosphorylation and nuclear localization of STAT3, together with IL-6/STAT3-responsive gene expression, were measured after both a single bout of resistance exercise and 10 weeks of training. Flexor Digitorum Profundus muscle samples from Wistar rats were obtained 2 and 6 hours after a single bout of resistance exercise and 72 h after the last bout of either 2, 4, or 10 weeks of resistance training. We observed an increase in IL-6 and SOCS3 mRNAs concomitant with phosphorylation of STAT1 and STAT3 after 2 and 6 hours of a single bout of exercise (p<0.05). STAT3-dependent early responsive genes such as CyclinD1 and cMyc were also upregulated whereas MyoD and Myf5 mRNAs were downregulated (p<0.05). BrdU-positive satellite cells increased at 2 and 6 hours after exercise (p<0.05). Muscle fiber hypertrophy reached up to 100% after 10 weeks of training and the mRNA expression of Myf5, c-Myc and Cyclin-D1 decreased, whereas IL-6 mRNA remained upregulated. We conclude that the IL-6/STAT1/STAT3 signaling pathway and its responsive genes after a single bout of resistance exercise are an important event regulating the SC pool and behavior involved in muscle hypertrophy after ten weeks of training in rat skeletal muscle.

Resistance Training Reduces Subclinical Inflammation in Obese, Postmenopausal Women

Aerobic exercise is frequently prescribed to reduce inflammatory-related disease (cardiovascular disease and diabetes) risk. Resistance training (RT), however, may be key to maximizing anti-inflammatory benefits of consistent exercise. We examined the influence of RT on inflammatory biomarkers in obese, postmenopausal women. Twenty-three women (65.6 ± 2.6 yr; body mass index, 33 kg·m) underwent 12 wk of RT (3 sets, 10 exercises, 3× per week, 8-12 repetition maximum (RM), resistance exercise (EX), N = 11) or social interaction intervention (SI, stretching, knitting, health lectures, 2× per week, control group (CON), N = 12). Both before (BT) and after (AT) RT or SI, blood was collected before (PR), immediately (PO), 2 h (2H), and 24 h (24H) after a single resistance exercise bout (RE) in EX and at the same time points in nonexercise, resting CON. For all time points, blood was analyzed for IL-6, leptin, and lipopolysaccharide (LPS)-stimulated tumor necrosis factor-α (TNF-α) (LPS-TNF) and IL-10 (LPS-IL10). PR samples were also examined for C-reactive protein, TNF-α, and adiponectin, and mRNA expression of toll-like receptor 4 (TLR4) and MC1R. Subcutaneous adipose tissue was extracted BT and AT and analyzed for mRNA expression of monocyte chemotactic protein-1, leptin, CD68, and TLR4. RT improved strength (44%) and reduced circulating C-reactive protein (-33%), leptin (-18%) and TNF-α (-29%) with no change in body composition. IL-6 decreased after SI in CON (-17%). LPS-TNF increased after SI or RT (CON +26%, EX +67%, respectively), whereas LPS-IL10 decreased in CON (-28%) but increased in EX (+20%). RT did not influence inflammatory biomarker gene expression in whole blood or subcutaneous adipose tissue. A single RE bout augmented LPS-TNF and LPS-IL10 at 24H in EX, particularly AT. RT reduced markers of subclinical inflammation in circulation in obese, postmenopausal women in the absence of changes in body composition. Chronic RT also enhanced response to endotoxin challenge both at rest (PR) and 24 h after an acute RE bout (24H).

Influence of carbohydrate supplementation during resistance training on concentrations of the hormones cortisol and insulin

This study analysed the influence of maltodextrin ingestion before and during a single bout of resistance exercise on muscle damage and catabolic/anabolic hormone responses. Seven young men previously trained in resistance exercises performed two sessions each comprising ten exercises for the upper limbs, accompanied by ingestion of a solution containing 8% carbohydrate or placebo. Blood samples were obtained before and after training for analysis of insulin, cortisol and creatine kinase, and during the training period (after the second, fourth, sixth, eighth and tenth exercise) for glucose analysis. At all time-points, glucose was found to be significantly higher following ingestion of carbohydrate. Although the training led to an increase in cortisol, no differences were noted between the carbohydrate and placebo sessions. However, the levels of insulin after training were approximately three times higher following ingestion of carbohydrate (28.7 ± 3 μU/ml) than following ingestion of placebo (9.5 ± 2.2 μU/ml, p <0.05. We conclude that carbohydrate ingestion before and during resistance exercises does not affect catabolic activity, but provides an important anabolic muscle stimulus.

Can a standard dose of eicosapentaenoic acid (EPA) supplementation reduce the symptoms of delayed onset of muscle soreness?

BackgroundUnaccustomed exercise can result in delayed onset of muscle soreness (DOMS) which can affect athletic performance. Although DOMS is a useful tool to identify muscle damage and remodelling, prolonged symptoms of DOMS may be associated with the over-training syndrome. In order to reduce the symptoms of DOMS numerous management strategies have been attempted with no significant effect on DOMS-associated cytokines surge. The present study aimed to investigate the acute and chronic effects of a 2 × 180 mg per day dose of eicosapentaenoic acid (EPA) on interleukin-6 (IL-6) mediated inflammatory response and symptoms associated with DOMS.MethodsSeventeen healthy non-smoking females (age 20.4 ± 2.1 years, height 161.2 ± 8.3 cm and mass 61.48 ± 7.4 kg) were randomly assigned to either placebo (N = 10) or EPA (N = 7). Serum IL-6, isometric and isokinetic (concentric and eccentric) strength, and rating of perceived exertion (RPE) were recorded on four occasions: i-prior to supplementation, ii-immediately after three weeks of supplementation (basal effects), iii-48 hours following a single bout of resistance exercise (acute training response effects), and iv-48 hours following the last of a series of three bouts of resistance exercise (chronic training response effects).ResultsThere was only a group difference in the degree of change in circulating IL-6 levels. In fact, relative to the first baseline, by the third bout of eccentric workout, the EPA group had 103 ± 60% increment in IL-6 levels whereas the placebo group only had 80 ± 26% incremented IL-6 levels (P = 0.020). We also describe a stable multiple linear regression model which included measures of strength and not IL-6 as predictors of RPE scale.ConclusionThe present study suggests that in doubling the standard recommended dose of EPA, whilst this may still not be beneficial at ameliorating the symptoms of DOMS, it counter intuitively appears to enhance the cytokine response to exercise. In a context where previous in vitro work has shown EPA to decrease the effects of inflammatory cytokines, it may in fact be that the doses required in vivo is much larger than current recommended amounts. An attempt to dampen the exercise-induced cytokine flux in fact results in an over-compensatory response of this system.

Creatine Supplementation Decreases Oxidative DNA Damage and Lipid Peroxidation Induced by a Single Bout of Resistance Exercise

Rahimi, R. Creatine supplementation decreases oxidative DNA damage and lipid peroxidation induced by a single bout of resistance exercise. J Strength Cond Res 25(12): 3448-3455, 2011-Creatine (Cr), or methyl guanidine-acetic acid, can be either ingested from exogenous sources, such as fish or meat, or produced endogenously by the body, primarily in the liver. It is used as an ergogenic aid to improve muscle mass, strength, and endurance. Heretofore, Cr's positive therapeutic benefits in various oxidative stress-associated diseases have been reported in the literature and, recently, Cr has also been shown to exert direct antioxidant effects. Therefore, the purpose of this study was to investigate the effects of an acute bout of resistance exercise (RE) on oxidative stress response and oxidative DNA damage in male athletes and whether supplementation with Cr could negate any observed differences. Twenty-seven resistance-trained men were randomly divided into a Cr supplementation group (the Cr group [21.6 ± 3.6 years], taking 4 × 5 g Cr monohydrate per day) or a placebo (PL) supplementation group (the PL group [21.2 ± 3.2 years], taking 4 × 5 g maltodextrin per day). A double-blind research design was employed for a 7-day supplementation period. Before and after the seventh day of supplementation, the subjects performed an RE protocol (7 sets of 4 exercises using 60-90 1 repetition maximum) in the flat pyramid loading pattern. Blood and urine samples taken before, immediately, and 24-hour postexercise were analyzed for plasma malondialdehyde (MDA) and urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) excretion. Before the supplementation period, a significant increase in the urinary 8-OHdG excretion and plasma MDA levels was observed after RE. The Cr supplementation induces a significant increase in athletics performance, and it attenuated the changes observed in the urinary 8-OHdG excretion and plasma MDA. These results indicate that Cr supplementation reduced oxidative DNA damage and lipid peroxidation induced by a single bout of RE.

Do whole-body vibration exercise and resistance exercise modify concentrations of salivary cortisol and immunoglobulin A?

A single bout of resistance exercise (RE) induces hormonal and immune responses, playing an important role in a long-term adaptive process. Whole-body vibration (WBV) has also been shown to affect hormonal responses. Evidence suggests that combining WBV with RE may amplify hormonal and immune responses due to the increased neuromuscular load. Therefore, the aim of this study was to evaluate salivary cortisol (Scortisol) and salivary IgA (SIgA) concentrations following a RE session combined or not with WBV. Nine university students (22.9 ± 5.1 years, 175.8 ± 5.2 cm, and 69.2 ± 7.3 kg) performed five sets of squat exercise (70% one-repetition-maximum) combined (R+V30) or not (R) with WBV at 30 Hz. Saliva samples were obtained before and after exercise. Subjects also rated their effort according to the Borg CR-10 scale (RPE). Data were analyzed by a mixed model. RPE was higher after R+V30 (8.3 ± 0.7) compared to R (6.2 ± 0.7). However, Scortisol (pre: 10.6 ± 7.6 and 11.7 ± 7.6, post: 8.3 ± 6.3 and 10.2 ± 7.2 ng/mL for R and R+V30, respectively) and SIgA concentrations (pre: 98.3 ± 22.6 and 116.1 ± 51.2, post: 116.6 ± 64.7 and 143.6 ± 80.5 µg/mL for R and R+V30, respectively) were unaffected. No significant correlations were observed between Scortisol and RPE (r = 0.45, P = 0.22; r = 0.30, P = 0.42, for R and R+V30, respectively). On the basis of these data, neither protocol modified salivary cortisol or IgA, although RPE was higher after R+V30 than R.

A single bout of resistance exercise does not affect nonlinear dynamics of lower extremity kinematics during treadmill walking

Peripheral fatigue has been known to result in altered force output and muscle recruitment patterns by the CNS. These changes may affect lower extremity movement during gait, and such behavior may present implications for the interpretation of nonlinear analysis of gait in situations where a subject might become fatigued. The purpose of this study was to examine the effects of a single bout of resistance training on lower extremity movement during treadmill walking in healthy subjects. Fifteen recreationally active subjects performed two 10 min trials of treadmill walking at their preferred speed while knee and ankle kinematics of their right limb were recorded via optical motion capture. Between walking trials, subjects performed a series of lower extremity resistance exercises designed to induce moderate muscular fatigue. Detrended fluctuation analysis of stride length and stride time revealed that statistical persistence was unaffected by moderate muscle fatigue. Estimates of finite-time maximal Lyapunov exponents for ankle angle, knee angle, and vertical ankle movement over the short (0–1 stride) and long (4–10 strides) term were also unaffected by a single bout of resistance training. These results suggest that control of locomotion in healthy individuals, as measured by the nonlinear dynamics of lower extremity movement used here, is relatively robust to moderate muscle fatigue. Additional work with greater levels of fatigue will be necessary to fully characterize the effects of muscular fatigue on gait.

Cardiovascular Workload After A Single Bout Of Resistance Exercise In Patients With Peripheral Arterial Disease

A single bout of resistance exercise decreases systolic blood pressure (SBP), suggesting that resistance exercise might be useful to reduce cardiovascular workload in peripheral arterial disease (PAD) patients. However, whether this response is accompanied by an increase in heart rate (HR) and rate pressure product (RPP) leading to an increase in cardiovascular workload remains unknown. PURPOSE. To analyze the effects of a single bout of resistance exercise on cardiovascular workload in patients with PAD. METHODS: Thirteen patients with PAD performed two experimental sessions in random order: control (C) and resistance exercise (R) sessions. Both experimental sessions were identical (six exercises, three sets of 10 repetitions), however while in the C session the intensity in all exercises was 0 in the Omni-Res scale, in the R session it was between 5-7. Before and at 10, 30 and 50 min after experimental sessions, SBP, HR, heart rate variability (HRV), and RPP were obtained. RESULTS. In comparison with pre-intervention values, SBP increased significantly after the C session during all the recovery stages (greatest increase = +10 ± 12 mmHg, P < 0.05), while it decreased significantly after the R session during all the recovery stages (greatest fall = -6±10 mmHg, P < 0.05). The changes in SBP after the R session were significantly greater than after the C session. In comparison with pre-intervention values, HR decreased significantly after the C session at all recovery stages (greatest fall = -7 ± 6 bpm, P < 0.05) and after the R session at 50 min of recovery (-3 ± 8, bpm, P < 0.05). The changes in HR after the C session were significantly greater than after the R session. After both experimental sessions the changes in HR were not enough to alter the HRV. RPP did not change significantly after both experimental sessions (P>0.05). CONCLUSION: A single bout of resistance exercise reduces SBP without increasing HR and RPP. Therefore, resistance exercise might be useful to decrease cardiovascular workload in PAD patients.

Cardiovascular and Metabolic Response to Resistance and Matched Aerobic Exercise

Little is known about metabolic and cardiovascular responses to resistance exercise (RE) compared to aerobic exercise (AE). PURPOSE: To measure cardiovascular (HR) and metabolic (VO2) responses to a single bout of RE which was then matched with bouts of AE for either HR or VO2 and time. METHOD: 16 males and 8 females participated. Air plethysmography measured body composition. Maximal oxygen uptake (VO2max) was measured during a standard treadmill test using open circuit spirometry. A 1-repetition maximum (1RM) test measured muscular strength for each RE. HR and VO2 were measured during a bout of a RE routine; 3 sets of 10 repetitions at 65% 1RM with 90 sec. of rest between each set. RE routine included: leg press, seated bench press, leg extension, bicep curls, shoulder press, lat pull-down, and tricep push-down. Randomized bouts of AE were completed; one to match VO2 of RE and one to match HR of RE. RESULTS: Age = 21.2 +/- 2.2 yr; BMI = 25.8 +/- 4.8 kg/m2; % fat = 22 +/- 9%; VO2max = 50.8 +/- 9.4 ml/kg/min; HR max = 193 +/- 7 bpm. Bouts of RE and AE were 40 minutes in duration. RE Work Time = 602 +/- 91 s; RE Rest Time = 1825 +/- 35 s. HR and VO2 did not significantly decrease during RE rest intervals compared to RE work intervals. VO2 during RE was significantly less than HR-matched AE. HR during VO2-matched AE was significantly lower than RE. RPE was significantly higher during and following RE as compared to either bout of matched AE.Table*denotes a significant difference between conditions; (p<0.05) CONCLUSION: Both HR and VO2 remained elevated during periods of rest between RE work; a bout of RE resulted in a significant caloric expenditure. However, RPE is greater during RE as compared to AE matched for either cardiovascular or metabolic loads.