Single Resistance Exercise Session Research Articles

One-week quercetin intervention modifies motor unit recruitment patterns before and during resistance exercise in older adults: A randomized controlled trial

We investigated the effects of one-week quercetin ingestion on motor unit (MU) behavior and muscle contractile properties before, during, and after a single session of resistance exercise in older adults. Twenty-four older adults were divided into two groups: those receiving quercetin glycosides (QUE) or placebo (PLA), and they performed a single session of resistance exercise. MU behavior before and during resistance exercise and electrically elicited contraction before and after resistance exercise were measured (Day 1), and the same measurements were conducted again after 7 days of placebo or quercetin glycoside ingestion (Day 8). The MU recruitment threshold (RT) was decreased (p < 0.001, 25.6 ± 10.1 to 23.6 ± 9.5 %MVC) and the exerted force normalized by the MU firing rate (FR) was increased (p = 0.003, 1.13 ± 0.24 to 1.18 ± 0.22 %MVC/pps) from Days 1 to 8, respectively, in QUE but not PLA (p = 0.263, 22.6 ± 11.9 to 21.9 ± 11.6 %MVC; p = 0.713, 1.09 ± 0.20 to 1.10 ± 0.19 %MVC/pps, respectively). On Day 1, a significant correlation between MURT and%change in MUFR from the first to last contractions during the resistance exercise was observed in both groups (QUE: p = 0.009, rs = 0.308; PLA: p < 0.001, rs = 0.403). On Day 8 %change in MUFR was negatively correlated with MURT in QUE (p = 0.044, rs = -0.251), but there was no significant correlation in PLA (p = 0.844). There was no difference in electrically elicited contraction before and after the resistance exercise between QUE and PLA (p < 0.05). These results suggest that one-week quercetin ingestion in older adults lowered MURT and led to greater fatigue in MU with higher RT than with lower RT during resistance training.

Differences in acute neuromuscular response after single session of resistance exercise between young and older adults

AimsThe purpose of this study was to investigate differences in the acute response after resistance exercise between young and older adults. MethodsSeventeen young and 18 older adults performed a single session of resistance exercise, consisting of 3 sets of 10 isometric knee extensions. Maximal voluntary contraction (MVC), motor unit (MU) activity of the vastus lateralis, and electrically elicited torque of the knee extensor were measured before and after the resistance exercise. ResultsAlthough both groups showed the same degree of decline in MVC (young: −15.2 ± 14.3 %, older: −16.4 ± 7.9 %, p = 0.839), electrically elicited torque markedly decreased in the young group (young: −21.5 ± 7.7 %, older: −14.3 ± 9.5 %, p < 0.001), and the decrease in the MU firing rate was greater in the older group (young: −26.1 ± 24.1 %, older: −44.7 ± 24.5 %, p < 0.001). Changes in the MU firing rate following the exercise were correlated with the MU recruitment threshold in the older group (p < 0.001, rs = 0.457), but not young group (p = 0.960). DiscussionThese results showed that young adults exhibited a greater acute response in the peripheral component, whereas older adults showed a greater acute response in the central component of the neuromuscular system, and the acute response in MUs with a high recruitment threshold following resistance exercise was smaller than in those with a low recruitment threshold in older adults. These findings may partly explain why there are different chronic adaptations to resistance training between young and older adults.

Effects of 7-day quercetin intervention on motor unit activity and muscle contractile properties before and after resistance exercise in young adults randomized controlled trials.

We investigated whether the alteration of the motor unit recruitment threshold (MURT) caused by quercetin ingestion intervention for 7 days modifies motor unit activation patterns before and after a single session of resistance exercise. Twenty young male and female adults were divided into two groups: ingestion of placebo (PLA) or quercetin glycosides at 200mg/day (QUE). High-density surface electromyography during submaximal contractions was measured to assess the motor unit firing rate (MUFR) and MURT of the vastus lateralis muscle before (PRE) and after (POST) resistance exercise (DAY1). The same measurements were repeated after 7 days of placebo or quercetin glycoside ingestion (DAY8). In QUE, MURT decreased more from DAY1-PRE to DAY8-PRE (29.1±9.1 to 27.1±9.5% MVC, p<0.001) but not in PLA (29.8±10.4 to 28.9±9.7% MVC, p<0.167). For percentage change in MUFR following resistance exercise, there was a significant interaction (day × group, p<0.001). The degree of changes in MURT from DAY1-PRE to DAY8-PRE was significantly correlated with the percentage change of MUFR from DAY8-PRE to DAY8-POST in QUE (p=0.014, r = -0.363) but not in PLA (p=0.518). The study suggests that 7-day quercetin ingestion alters the motor unit recruitment pattern, and this may induce changes in motor unit firing patterns during a single session of resistance training (Trial registration: UMIN000052255, R000059650).

A single session of hip abductors resistance exercise until failure changes shank muscle activation during landing tasks

BACKGROUND: Weakness in the hip abductors can lead to lower limb misalignment and an elevated risk of injury. This can result in compensatory mechanisms at the ankle to maintain stability. AIM: To verify the effects of a single session of hip abductors resistance exercise until failure on the foot pronation and EMG amplitude of shank muscles (peroneus longus - PL; tibialis anterior - TA) during landing tasks. METHOD: Seventeen participants completed single-leg and double-leg landings both before and after a single session of hip abductors resistance exercise until failure. The exercise consisted of four sets of 10 repetitions maximum, with a 2-minute rest interval between each set. Measurements of PL and TA EMG amplitude and degree of foot pronation were performed during landings. RESULTS: We observed a greater degree of supination of the foot during single-leg compared to double-leg landing (p=0.006), without effect of exercise. Regarding TA EMG amplitude, there was no exercise effect (p=0.951), with a higher amplitude observed in double-leg compared to single-leg landing (p=0.001). EMG amplitude of PL was higher during single-leg compared to double-leg landing (p=0.003) and the exercise significantly reduced its activation in both tasks (p=0.032). CONCLUSION: Single-leg and double-leg landings exhibited variations in mechanics and activation patterns of the distal muscles. Following a single session of hip abductors resistance exercise until failure, there was a reduction in PL activation during landing tasks. This suggests that there were neuromuscular compensations occurring distally due to alterations in the hip abductor muscles.

Effect of a single resistance exercise session on inflammatory markers and oxidative stress in women living with HIV

People living with HIV (PLH), who use antiretroviral therapy (ART), are more susceptible to changes in the inflammatory profile and oxidative stress, and women have greater access to ART. Although physical exercise is a complementary strategy to treatment due to its antioxidant and anti-inflammatory effects, it is not clear whether acute responses to exercise can be harmful to PLH. The aim of the study was to investigate the acute effect of resistance exercise (RE) on inflammatory and oxidative stress markers in PLH. Ten women, using ART, performed RE session consisting of seven exercises for the whole body. For biochemical evaluation, blood samples were collected before (pre), 1 hour (1h) and 2 hours (2h) after the RE session. One-way ANOVA followed by Bonferroni's post hoc test was used to compare results between time points. There was an increase only in markers, GSSG of 160% (pre: 0.40 ± 0.11; 1h: 1.18 ± 0.36; 2h: 1.04 ± 0.25 mmol/g), TNF-α of 98 % (pre: 4.60 ± 0.55; 1h: 6.95 ± 0.77; 2h: 9.10 ± 1.03 pg/ml) and 52% IL-6 (pre: 2.47 ± 0 .67; 1h: 3.63 ± 1.26; 2h: 5.38 ± 2.15 pg/ml). The other variables remained unchanged (P &gt; 0.05). It is concluded that a RE session increased the levels of inflammatory markers and oxidative stress in PLH in a non-exacerbated way.

Acute bouts of aerobic and resistance exercise similarly alter inhibitory control and response time while inversely modifying plasma BDNF concentrations in middle-aged and older adults with type 2 diabetes.

Impairments in several domains of cognitive functions are observed in people with Type 2 Diabetes Mellitus (T2DM), often accompanied by low Brain-derived neurotrophic factor (BDNF) concentrations. Although aerobic and resistance exercise enhances cognitive functions and raises BDNF concentrations in several populations, it remained uncertain in T2DM subjects. This study compared the effects of a single bout of aerobic (AER, 40min of treadmill walk at 90-95% of the maximum walk speed) or resistance (RES, 3 × 10 repetitions in eight exercises at 70% of 10-RM) exercise on specific cognitive domain performance and plasma BDNF concentrations of physically active T2DM subjects. Eleven T2DM subjects (9 women/2 men; 63 ± 7years) performed two counterbalanced trials on non-consecutive days. Stroop Color and Word (SCW) task [assessing the attention (congruent condition) and inhibitory control (incongruent condition)], Visual response time (assessing the response time), and blood collection (for plasma BDNF concentrations) were performed pre and post-exercise sessions. With distinct magnitude, both AER and RES improved the incongruent-SCW (d = -0.26 vs. -0.43 in AER and RES, respectively; p < 0.05), RT(best) (d = -0.31 vs. -0.52, p < 0.05), and RT(1-5) (d = -0.64 vs. -0.21, p < 0.05). The congruent-SCW and RT(6-10) were not statistically different. Plasma BDNF concentrations were elevated 11% in AER (d = 0.30) but decreased by 15% in RES (d = -0.43). A single session of aerobic or resistance exercise similarly improved the inhibitory control and response time of physically active T2DM subjects. Nevertheless, aerobic and resistance exercise sessions induced an opposite clinical effect in plasma BDNF concentrations.

Preliminary feasibility and acute physiological effects of a single session of upper limb vibration training for persons with spinal cord injury

Context Strong upper limb musculature is essential for persons with spinal cord injury (SCI) to operate a manual wheelchair and live independently. Targeted upper limb vibration may be a viable exercise modality to build muscle efficiently while eliminating some of the barriers associated with exercise for persons with SCI. Objective The purpose of this study was to assess preliminary feasibility of completing a single exercise session of upper limb vibration and compare the acute physiological effects to a single session of standard dumbbell resistance exercise. Methods Individuals with SCI performed seven upper limb exercises (1) isometrically using a vibrating dumbbell at 30 Hz for 60 s (n = 22) and (2) using a standard isotonic resistance protocol (n = 15). Results Nineteen (86.4%) of 22 participants were able to perform all vibration exercises at 30 Hz but hold time success rates varied from 33% (side flies and front raises) to 95% (internal rotation). No significant differences were found between vibration exercise and standard resistance protocol for blood lactate, power output, and heart rate (P > 0.05). Perceptions of the training were positive, with most participants (>70%) expressing interest to train with vibration in the future. Conclusions Vibration training was not feasible for all participants, suggesting an individualized approach to starting weight and progression may be necessary. Similar acute physiological changes were seen between vibration exercise and standard resistance protocol, suggesting they could have similar benefits. Additional research is needed to determine if vibration exercise is feasible and beneficial to incorporate into a long-term training program.

The Skeletal Muscle Metabolome Reflects Resistance Exercise-induced Skeletal Muscle Adaptation

PURPOSE: It is unknown how acute resistance exercise (RE) affects the human skeletal muscle metabolome and whether chronic RE will further change this response. Aim: To investigate the skeletal muscle metabolome acutely after a single RE session in the unadapted state and after a resistance training programme in the adapted state. METHODS: Six healthy male volunteers conducted 13 RE-bouts resistance training programme over five weeks. Vastus lateralis muscle biopsies were taken at rest, 45 min after the first and last bout of RE. Skeletal muscle metabolite levels were measured by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) following database-assisted metabolite annotation (Metabolon). RESULTS: We measured the relative abundance of 617 metabolites covering a broad range of metabolic pathways including protein breakdown, energy-, lipid- and nucleotide metabolism. While acute, unaccustomed RE changed the levels of 33 metabolites repeated RE training altered the concentration of 46 metabolites after RE in the trained state. During the study, slow type I and fast/intermediate type II muscle fibre diameter increased by 10.7% and 10.4%, respectively. Importantly, after RE we detected significant increases in the bile acid metabolite chenodeoxycholate and beta-citrylglutamate which support a growth-promoting environment in tissues. While we were able to support findings previously obtained in plasma, some results contradict those findings and emphasize a direct analysis of the skeletal muscle metabolome to be advantageous. CONCLUSIONS: The skeletal muscle metabolome is sensitive towards acute RE in the trained and untrained state and partly reflects the adaptive process of skeletal muscle towards repeated stimulation.

Acute imagery resistance exercise improves subsequent muscle power performance in teenage futsal athletes

Background: Futsal is one of the most popular sport in Brazil with millions of players worldwide. It is characterized by intermittent stimuli of high intensity anaerobic actions. Recently, studies have shown that imagery resistance training (IRT), like conventional strength training, can increase muscle strength, making it reasonable to think that this effect can also be transferred to muscle power. Purposes: we aimed to verify the acute responses of IRT on muscle power in teenage Futsal players. Methods: fifteen Futsal athletes were enrolled and underwent three visits to the laboratory: 1) familiarization with the resistance exercise they would undergo; 2) one them for vertical jump test after the IRT session and the other one for control session, without any intervention before vertical jump test. Sessions 2 and 3 being applied in random order. Results: the results indicate that acute IRT improved muscle performance, since it produced higher power output [3134.5 Watts (2744 - 3796.3)] than control session [2952.4 Watts (2637.55 - 3433.45)] (Z=3.4078; p=0.0007). In addition, all participants in IRT group showed some improvement after the IRT session. Conclusions: a single imagery resistance exercise session can increase acute muscle power output in teenage Futsal athletes.

Central Hemodynamic Adjustments during Post-Exercise Hypotension in Hypertensive Patients with Ischemic Heart Disease: Concurrent Circuit Exercise versus High-Intensity Interval Exercise. A Preliminary Study.

Concurrent aerobic plus resistance exercise (RAE) and high-intensity interval exercise (HIIE) are both effective at inducing post-exercise hypotension (PEH) in patients with hypertension. However, central hemodynamic changes associated with PEH in hypertensive subjects with underlying ischemic heart disease (IHD) have been poorly investigated. The study aim was to compare the acute effects produced by these two exercise modalities on left ventricular diastolic function and left atrial function. Twenty untrained male patients with a history of hypertension and IHD under stable pharmacological therapy were enrolled. Each patient underwent three exercise sessions: RAE, HIIE and a control session without exercise, each lasting 45 min. An echocardiography examination was performed before and between 30 min and 40 min from the end of the exercise sessions. Following the exercise sessions, BP values decreased in a similar way in RAE and HIIE and were unchanged after the control session. Compared to pre-session, the ratio between early filling velocity (E) and mitral annulus early diastolic velocity (E’). E/E’ increased after HIIE and remained unchanged after both RAE and control sessions (between-sessions p 0.002). Peak atrial longitudinal strain (PALS) increased slightly after RAE (+1.4 ± 1.1%), decreased after HIIE (−4.6 ± 2.4%) and was unchanged after the control session (between-sessions p 0.03). Peak atrial contraction strain (PACS) was mildly increased after RAE, was reduced after HIIE and was unchanged after the control session. Atrial volume was unchanged after both exercise sessions. Left ventricular and left atrial stiffness increased significantly after HIIE, but remained unchanged after the RAE and control sessions. Stroke volume and cardiac output increased after RAE, decreased after HIIE, and were unchanged after the control session. In conclusion, single session of RAE and HIIE brought about similar PEH in hypertensive subjects with IHD, while they evoked different central hemodynamic adjustments. Given its neutral effects on diastolic and atrial functions, RAE seems more suitable for reducing blood pressure in hypertensive patients with IHD.

Acute effects of different types of exercise on the blood pressure of hypertensive older women: a randomized study.

The magnitude and duration of the hypotensive effect of exercise may be influence by the type of exercise performed. The aim of the present study was to compare systolic (SBP) and diastolic (DBP) blood pressure for 24 hours after a single session of continuous aerobic (CA), interval aerobic (IA), resistance (RE) exercise and control (C), among hypertensive older women under treatment. The study was conducted on 30 women aged 67.5±5.2 years participating in all sessions applied in random order. After each session, blood pressure was obtained by an oscillometric device and they were submitted to 24-hour ambulatory blood pressure monitoring. Immediately after the sessions, a lower SBP value was observed in groups CA and IA compared to groups C and RE. During the 24 hours after sessions, there was a greater reduction of SBP after IA than after other types of exercise, with the reduction after RE being greater than after CA and C (P<0.01). In wakefulness period, the reduction of SBP after IA was more intensive, and, during sleep, IA and RE promoted greater reductions of SBP, with reduction of DBP only after RE (P<0.01). Immediately after the exercise sessions there was a fall in SBP only after aerobic exercises. However, aerobic exercise in the interval mode and RE were more effective in reducing BP over a period of 24 hours.

Substrate metabolism during recovery from circuit resistance exercise in persons with spinal cord injury.

Whole body energy expenditure and lipid oxidation (Lox) are upregulated during and after exercise. Persons with spinal cord injury (SCI) generally have a blunted ability to utilize fat during exercise, but it is unknown if their substrate partitioning is affected during recovery from exercise. To determine the effect of a single session of upper body circuit resistance exercise (CRE) on energy expenditure and Lox during exercise recovery in persons with and without SCI. Twenty four persons (3 groups; 7 male and 1 female per group) without paralysis (neurologically intact; N) or with chronic (≥ 1yr) paraplegia (P) or tetraplegia (T) participated. Energy expenditure and substrate partitioning were assessed via indirect calorimetry before, during, and three times after (up to 120min after) a single session of CRE, or time-matched seated control (CON). During CRE, all groups experienced a similar relative increase in oxygen consumption (49 ± 13, 55 ± 11, and 48 ± 15% VO2peak for N, P, and T, respectively). The Post0-120 energy expenditure was greater following CRE vs. CON (P < 0.01) and independent of injury characteristics (10.6, 22.6, and 14.3% higher than CON for N, P, and T; P = 0.21). The absolute increase in Lox above CON during recovery was similar for N, P, and T (5.74 ± 2.81, 6.62 ± 3.10, and 4.50 ± 3.91g, respectively; P = 0.45). Energy expenditure and lipid utilization was increased similarly following circuit exercise in persons without and with spinal cord injury in a manner independent of level of injury.

Association between pulmonary oxygen uptake on-kinetics and acute cardiovascular responses to resistance exercise in patients with coronary artery disease: a preliminary study.

[Purpose] This study aimed to examine whether pulmonary oxygen uptake on-kinetics at the onset of moderate-intensity exercise can predict acute cardiovascular responses to resistance exercise. [Participants and Methods] The association between pulmonary oxygen uptake on-kinetics and acute cardiovascular responses to a single resistance exercise session was investigated in seven patients with low-risk coronary artery disease who underwent revascularization through percutaneous coronary intervention. The participants performed a cardiopulmonary exercise test on a cycle ergometer and a single resistance exercise session at 30% of maximum voluntary contraction on a bilateral leg-extension machine 1 week after surgery. We measured the ventilatory anaerobic threshold and pulmonary oxygen uptake on-kinetics during the cardiopulmonary exercise test; left ventricular ejection fraction at rest; and heart rate, systolic blood pressure, and rate pressure product during the single resistance exercise session. [Results] Pulmonary oxygen uptake on-kinetics showed a positive association with the amount of increase in systolic blood pressure and rate pressure product during the single resistance exercise session, but had no association with the amount of increase in heart rate. Ventilatory anaerobic threshold and left ventricular ejection fraction were not associated with these parameters. [Conclusion] These data suggested that pulmonary oxygen uptake on-kinetics can be a useful evaluation index for predicting acute systolic blood pressure and rate pressure product responses to low-intensity resistance exercise 1 week after percutaneous coronary intervention in patients with low-risk coronary artery disease.

Acute effect of resistance exercise on cognitive function in people living with HIV

People living with HIV are at an increased risk of developing cognitive deficits. Physical exercise is an important strategy to improve the brain health of people living with HIV. This randomized, controlled study aimed to investigate the acute effect of a single resistance exercise session on the cognitive function of people living with HIV. Twenty-three people living with HIV were randomized (1:1) to a control group (n = 12) or the exercise group (n = 11). Cognitive function was assessed by the Stroop test and the Trail Making Test. The exercise group was evaluated before and after the exercise session; meanwhile, the control group was evaluated before and after a 40-minute rest period. No statistical difference was found on the effect of exercise on cognitive function (p > 0.05). This result suggests that one session of resistance exercise was not capable of improving the cognitive function of people with HIV.

Flow-Mediated Dilation in Healthy Young Individuals Is Impaired after a Single Resistance Exercise Session.

The current pool of data investigating the effects of a single resistance exercise session on endothelial function is divergent and inconclusive. Therefore, the purpose of the present study was to evaluate the effect of a single resistance exercise session on flow-mediated dilation (FMD) in trained individuals. Eleven healthy, young, recreationally resistance-trained individuals participated in the study. After determining the resistance exercise workload, the participants performed three sets of 10–12 repetition of leg press and leg extension exercises. By using ultrasound equipment, brachial artery FMD was assessed before (PRE) and 30 min after (POST) the resistance exercise protocol or resting (control) to evaluate endothelial function. A significant reduction in FMD response (PRE: 5.73% ± 1.21% vs. POST: 4.03% ± 1.94%, p < 0.01) after resistance exercise was observed, accompanied by a large effect size (d = 1.05). No significant difference was observed in FMD in the control condition (PRE: 5.82% ± 1.19% vs. POST: 5.66% ± 1.24%, p = 0.704). Additionally, no significant difference in baseline brachial artery diameter between resistance exercise (PRE: 3.30 ± 0.32 vs. POST: 3.40 ± 0.34 mm, p = 0.494) and resting (PRE: 3.64 ± 0.41 vs. POST: 3.67 ± 0.62 mm, p = 0.825) was observed. Our findings showed that a single resistance exercise session induced a reduction in FMD in resistance-trained individuals.

Similar Energy Expenditure During BodyPump and Heavy Load Resistance Exercise in Overweight Women.

PurposeHigh-repetition, low-load resistance exercise in group class settings has gained popularity in recent years, with BodyPump as a prime example. For individuals using exercise for body-weight management, the energy expenditure during exercise is of interest. Therefore, we herein aimed to estimate the energy expenditure during a session of BodyPump and a time-matched session of heavy load resistance training in overweight women (BMI ≥ 25.0).MethodsEighteen women participated in the study (mean age 35.4 years ± 10.2, BMI 30.4 kg/m2 ± 4.8), 10 exercising BodyPump (50–100 repetitions each muscle group) and eight performed a heavy load session (eight repetition maximum × three sets). The energy expenditure was assessed with indirect calorimetry during the sessions and for two intervals at rest during the recovery phase: 0–20 and 120–140 min after the sessions.ResultsThe BodyPump group lifted significantly more loads than the heavy load group (19,485 kg ± 2258 vs 15,616 kg ± 2976, p = 0.006), while energy expenditure was similar with 302 kcal ± 67 and 289 kcal ± 69 in BodyPump and heavy load group, respectively (p = 0.69). With no group differences, the resting metabolic rate (RMR) was elevated with 15–22% 2 h after exercise.ConclusionOverweight women achieved an energy expenditure of approximately 300 kcal (4.7 kcal per min) during a single session of BodyPump, which was similar with the women performing a single session of heavy load resistance exercise.

Exercise: A Protective Measure or an "Open Window" for COVID-19? A Mini Review.

The coronavirus disease 2019 (COVID-19) has spread to at least 115 countries and caused an alarming number of deaths. The current outbreak has lead authorities from many countries to adopt several protective measures, including lockdown and social distancing. Although being a reasonable measure to counteract the COVID-19 contamination, the restrictive measures have limited individual's ability to perform exercise outdoors or in gyms and similar facilities, thus raising the risks for chronic health conditions related to a sedentary lifestyle. The recent exercise recommendations to counteract the potential deleterious effects of COVID-19-related lockdown have not fully addressed resistance exercise interventions as potential home-based exercise strategies. Additionally, the following questions have been constantly raised: (1) Is training status capable of protecting an individual from COVID-19 infection?; and (2) Can a single endurance or resistance exercise session acutely increase the risks for COVID-19 infection? Therefore, the current mini review aimed to focus on these two concerns, as well as to discuss the potential use of practical blood flow restriction and no load resistance training as possible resistance exercise strategies that could be performed during the current COVID-19 pandemic.

Tribulus Terrestris may decrease muscle damage markers following a high-intensity resistance exercise: A pilot study.

The purpose of this study was to investigate the effect of two weeks of Tribulus Terrestris (TT) on the responses of Interleukin-6 (IL-6), high sensitivity C-reactive protein (hs-CRP), and enzymes creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) following a single session of resistance exercise (RE). Eighteen healthy non-athlete males (age: 22.44 ± 2.54 years, BMI: 26.15 ± 1.62 kg/m2) participated in this study and were divided randomly into two 9-person groups of supplementation or placebo. The participants consumed two 250-mg capsules of TT or placebo (maltodextrin) per day and performed six REs with the intensity 80, 85, and 90% of 1RM in three circles at the day after the end of supplementation period. Blood samples were collected before the initiation of supplementation, and before and after the RE session. Total changes of IL-6 (p<0.001) and LDH (p=0.005) were significant in both groups. Bonferroni post hoc test showed that increased values of IL-6 and CPK in both groups were significant after exercise compared with pre-exercise and baseline (p<0.001). There were no significant differences in relation to within- and between-group changes in hs-CRP (p>0.05). Moreover, differences between the groups regarding post-exercise IL-6 and CPK were not significant (p>0.05). However, post-exercise LDH in supplementation group were lower than placebo group (p=0.015). In conclusion, short-term supplementation with TT has no effect on IL-6 and hs-CRP, but may be effective on the reduction of muscle damage enzymes CPK and LDH following high-intensity circuit RE.

Can IGF-1 Serum Levels Really be Changed by Acute Physical Exercise? A Systematic Review and Meta-Analysis.

Physical exercise plays an important role in metabolic health, especially in the insulin-like growth factor-1 (IGF-1) system. The objective of this study was to perform a systematic review and meta-analysis to evaluate the effects of a single endurance and resistance exercise session on IGF-1 serum. The systematic review was performed in SPORTDiscus, MEDLINE, PubMed, and Google Scholar databases. All analyses are based on random-effect models. The study identified 249 records of which 21 were included. There was an effect of endurance exercise on total IGF-1 (P = .01), but not for free IGF-1 (P = .36). Resistance exercise similarly only affected total IGF-1 (P = .003) and not free IGF-1 (P = .37). The effect size indicated that total IGF-1 is more affected (ES = 0.81) by endurance than by resistance exercise (ES = 0.46). The present study showed that IGF-1 serum concentrations are altered by exercise type, but in conditions which are not well-defined. The systematic review and meta-analysis suggest that there is no determinant in serum IGF-1 changes for the exercise load characteristic. Therefore, physical exercise may be an alternative treatment to control changes in IGF-1 metabolism and blood concentration.

Ischemic Preconditioning Improves Resistance Training Session Performance.

da Silva Novaes, J, da Silva Telles, LG, Monteiro, ER, da Silva Araujo, G, Vingren, JL, Silva Panza, P, Reis, VM, Laterza, MC, and Vianna, JM. Ischemic preconditioning improves resistance training session performance. J Strength Cond Res 35(11): 2993-2998, 2021-The aim of this study was to investigate the acute effect of ischemic preconditioning (IPC) in a resistance exercise (RE) training session on the number of repetitions performed, total volume, and rating of perceived exertion in recreationally trained and normotensive men. Sixteen recreationally trained and normotensive men completed 3 RE sessions in a counterbalanced and randomized order: (a) IPC protocol using 220 mm Hg followed by RE (IPC), (b) IPC cuff control protocol with 20 mm Hg followed by RE (CUFF), and (c) no IPC (control) followed by RE (CON). RE was performed with 3 sets of each exercise (bench press, leg press, lateral pulldown, hack machine squat, shoulder press, and Smith back squat) until concentric muscular failure, at 80% of one repetition maximum, with 90 seconds of rest between sets and 2 minutes of rest between exercises. Ischemic preconditioning and CUFF consisted of 4 cycles of 5 minutes of occlusion/low pressure alternating with 5 minutes of no occlusion (0 mm Hg) using a pneumatic tourniquet applied around the subaxillary region of the upper arm. For each condition, the number of repetitions completed, total volume of work performed, and rating of perceived exertion were determined. No significant difference was found for rating of perceived exertion between any experimental protocol. Ischemic preconditioning significantly (p < 0.05) increased the number of repetitions across exercises. Consequently, total volume performed (sum of total number of repetitions x load for each exercise) was significantly higher in IPC (46,170 kg) compared with CON (34,069 kg) and CUFF (36,590 kg) across all exercises. This work may have important implications for athletic populations because it demonstrates increase in muscle performance outcomes during a single RE session. Therefore, performing IPC before RE could be an important exercise prescription recommendation to increase maximum repetition performance and total volume of work performed and thus potentially increase desired training adaptations (i.e., strength and hypertrophy).