Electromyographic activity of elderly vastus lateralis oblique muscle submitted to periodized resistance training

Resistance training (RT) is recommended for elderly with the objective to increase muscle strength and power trough neuromuscular adaptations, inducing increased motor and functional capacities. The electromyography (EMG) is an important instrument to analyze muscle function after diverse exercise training protocols. The objective of the present study was to analyze electromyographic activity of vastus lateralis oblique muscle (VLO) during maximal voluntary isometric contraction of elderly women submitted to 12 weeks of periodized RT. 16 women aged 65.5±3.6 years with a minimum of one year of previous experience in strength training were selected, they performed 24 sessions of RT divided in 3 mesocycles (MA, MB and MC), of 8 sessions each, with a session frequency of twice a week. The MA with light intensity, the MB moderate and the MC with high intensity. Training intensity was measured by the Borg perception scale. For statistical analysis a p\u3c0.05 was assumed. There was a significant increase in root mean square (RMS) at 90º of knee flexion after 12 weeks (T2) compared with T1 (baseline), measured by VLO muscle EMG. Periodized RT in elderly women is efficient in increasing muscle force, induced by an increase in muscle fiber depolarization

Assessment of the heart rate in judo athletes

Judo is a martial art of Nippon Foundation origin which has been showing excellent results by Brazilian judokas in international competitions. In match dominates the use of anaerobic lactic metabolim, supported by high concentrations of blood lactate found and characteristic of intermittent exercises during the fights. The aim of this study was to evaluate the intensity of exercise in the Judo fight, comparing the heart rate between the light and heavy categories. Five male judokas, aged 20.6 ± 5.4 years, body mass of 87.9 ± 24.1 kg, from a competitive team. All the athletes were subjected to at least a fight with an opponent in its weight category and another of a different category. The fight had five minutes duration, and the heart rate was measured at intervals of 1 minute with a heart rate monitor (Polar®). Most of the time, the heart rate was above the 160 bpm (anaerobic zone), in all the fights at both categories. In conclusion, the findings show the dominance of anaerobic metabolism in Judo, demonstrated by high heart during the fights, with no differentiation of the predominance of metabolism between the light and heavy categories

Changes in heart rate and blood pressure in sub-18 soccer players tested with Running-Based Anaerobic Sprint Test

The Running-Based Anaerobic Sprint Test (RAST) is an important tool for prescribing and monitoring training. The aim of this study was to evaluate cardiovascular changes by the variables heart rate and blood pressure in soccer players tested with RAST. A trial with 20 soccer players who trained daily and participated in sub-18 soccer championships. The heart rate (HR) was collected at rest (before warming) and right after the end of the test, as well as the systolic (SBP) and diastolic (DBP) blood pressure. For statistics it was used the paired t-test with p\u3c0.05. The collected data show that the values at resting time point can be considered normal for healthy young people and after the test it was observed that the HR and SBP increased significantly as compared with resting time, and the DPB presented no statistically changes. Conclusion: The results showed that the cardiovascular changes occurring in the RAST test, which is an effort with anaerobic features, are similar to changes in high-intensity aerobic efforts

Increase in muscle power induced by periodized resistance training in elderly women

Resistance training (RT) has been recommended to prevent muscle force and power decrease induced by aging. Neuromuscular tests are important tools to analyze muscle force function. The objective of the present study was to analyze the behavior of lower limb muscle power of elderly women submitted to 12 weeks of periodized RT. 16 women aged 65.5±3.6 years with a minimum of one year of previous experience in strength training were selected, they performed 24 sessions of RT divided in 3 mesocycles (MA, MB and MC), of 8 sessions each, with a session frequency of twice a week. The MA with light intensity, MB moderate and MC with high intensity. Lower limb muscle power was measured by vertical jump test. For statistical analysis a p\u3c0.05 was assumed. There was a significant increase in vertical jump after four (T2), eight (T3) and 12 weeks (T4) as compared with baseline (T1). Periodized RT induced positive effects on lower limb muscle power in elderly women. These results are very important for aging, since higher loses in muscle force are observed in lower limb. Periodization is an important tool to prolong the results of muscle power increase induced by RT

Exercise-Induced Muscle Damage and Running Economy in Humans

Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (~15–30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VO2max). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (~90% VO2max). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE

Neuromuscular parameters and anaerobic power of U-20 futsal players

The current investigation aimed to find the difference between right and left lower limb strength of quadriceps and hamstring muscles and describe young futsal players’ explosive strength and anaerobic power. The study comprised 12 university male U-20 futsal players (74.5 ± 9.7 kg;173.2 ± 7.2 cm; 18.7 ± 1.2 yrs.). Isometric strength was measured using an isometric dynamometer, lower limb explosive strength was assessed through the Countermovement Jump and anaerobic power was estimated with the Wingate test. Initially, results were displayed through descriptive statistics. Magnitude-based inference with respective Confidence Intervals (CI=90%) and effect size were used to compare inter-lower limb strength. No substantial differences were found between right and left lower limb, to knee extension and flexion. Team’s explosive strength and anaerobic power were 36.7 ± 7 cm and 998.3 ± 125.9 W, respectively. These findings suggest that young futsal players’ performance may be less affected due to inter-lower limb asymmetries

W Prime: Evidence-Based Proposal for a New Predictor of Gait Speed in Older Women

Background: The hyperbolic torque-duration curve depicts critical torque (CT) and W prime (W′), with the curve’s asymptote representing CT as the boundary between heavy- and severe-intensity domains. W′, the curvature constant, indicates cumulative work beyond CT. This study investigated age-related reductions in W′, CT, and gait speed, and whether W′ and CT predict gait speed independently of muscle torque. Methods: three groups (adults, middle-aged, older) totaling 131 women were studied. W′ and CT were determined using 60 maximal isometric voluntary contractions of knee extensors. The fast gait speed was calculated in walking tests at 10 m, 400 m, and six minutes (6 MWT). Results: gait speed decreased (p p < 0.05) with all gait speed tests (10 m: β = 0.201, SE = 0.086; 400 m: β = 0.262, SE = 0.085; 6 MWT: β = 0.187, SE = 0.086). Conclusions: aging led to declines in W′, CT, and gait speed. W′, not CT, remained a significant predictor of gait speed, indicating its importance for older women’s mobility

Cardiovascular Responses to Unilateral, Bilateral, Upper, and Lower Limbs Resistance Exercises

International Journal of Exercise Science 16(2): 1154-1164, 2023. The effects of different resistance exercises on cardiovascular responses remain elusive. Therefore, the present study aimed to investigate acute cardiovascular responses to unilateral and bilateral upper and lower limb resistance exercise. Young healthy males (n = 22; 26.9 ± 5.4 years, 170.0 ± 6.0 cm, 77.0 ± 10.8 kg) participated in the present study. Four experimental sessions were carried out, each consisting of one of the four exercises: unilateral and bilateral knee extension, unilateral and bilateral biceps curl. Cardiovascular responses (heart rate; HR, systolic blood pressure; SBP, and rate-pressure product; RPP) were measured at rest and after each of the three sets in each resistance exercise. All sets were performed until concentric muscle failure with a rest interval of two min. The HR, SBP, and RPP progressively increased during all sessions with uni- and bilateral exercises of the lower and upper limbs. Importantly, bilateral exercises, mainly of the lower limbs, induced greater increases in HR, and RPP than unilateral exercises of the upper and lower limbs. Regarding SBP, bilateral knee extension exercise induced greater increases than unilateral biceps curl. From a practical standpoint, exercise professionals may consider prescribing unilateral upper and lower limb exercises to alleviate cardiovascular stress, because even when performed until concentric muscle failure, this exercise mode seems to induce lower cardiovascular demand during the resistance training session

Analysis of Muscle Strength and Electromyographic Activity during Different Deadlift Positions

The aim of the study was to analyze muscle activation in the three positions of the deadlift (DL). Twenty male participants (33.4 ± 3.9 years; 42.2 ± 9.1 months of experience with DL; 91.0 ± 14.8 kg; and 1.78 ± 0.06 m) pulled a bar through isometric actions in three DL positions: lift-off, mid-pull, and lockout. Isometric strength, knee angle, and activation of the rectus femoris (RF), biceps femoris (BF), lateral gastrocnemius (GAL), and erector spinae (ERE) muscles were collected. The analysis of variance showed that the maximum isometric force presented differences between the positions (p = 0.001; η2 = 0.973) considered large with higher values at the mid-pull position. Interactions were found between muscles and position (p = 0.001; η2 = 0.527) considered large. The RF and ERE showed greater activation in the lift-off position, while in the mid-pull position, there was greater activation of the BF and GAL muscles. The DL positions produce different activations in the bi-articular and uni-articular muscles. The lift-off requires more activation from the RF and ERE positions. The mid-pull position, despite generating greater force, presented greater activations in the BF and GAL. The ERE showed higher activations as the external torque was greater