Effect of Different Types of Lower-limb Exercise on Blood Pressure in Hypertensive People: A Randomized, Double-blind Controlled Clinical Trial

Objectives: The current study aimed at determining the immediate and long-lasting effects of eccentric and concentric exercises on hypertension in individuals with high blood pressure. Methods: A total of 45 hypertensive volunteers were randomly assigned to three intervention groups as eccentric exercise (n = 15), concentric exercise (n = 15), and control (n = 15) groups. All the volunteers underwent exercise interventions for four weeks, three sessions per week (12 sessions in total) as treadmill walking with +10% gradient (concentric group), -10% gradient (eccentric group), or neutral gradient. Before the intervention, immediately after the first session of the intervention, after the end of the intervention, and 48 hours after the end of the intervention, systolic and diastolic blood pressure, heart rate, and maximum oxygen consumption were measured and compared between the groups. Results: The positive gradient group had higher diastolic blood pressure 48 h after the intervention than the negative and neutral gradient groups (P < 0.05). There was no significant difference in the other study variables between eccentric and concentric exercise groups (P > 0.05). Statistical analysis showed that eccentric exercises immediately reduced systolic and diastolic blood pressure (P < 0.05). Eccentric and constrictive exercises reduced systolic and diastolic blood pressure for the long term (P < 0.05). Exonerative and constrictive exercises improved the heart rate, maximum oxygen consumption, and systolic blood and diastolic blood pressure in the short and long term (P < 0.05). Conclusions: Eccentric and concentric exercises with immediate and long-lasting effects improved systolic and diastolic blood pressure, as well as heart rate and maximum oxygen consumption. No significant difference was found between the two types of exercises in terms of the variables studied.

Aerobic Metabolic Adaptations in Endurance Eccentric Exercise and Training: From Whole Body to Mitochondria

A characteristic feature of eccentric as compared with concentric exercise is the ability to generate greater mechanical loads for lower cardiopulmonary demands. Current evidence concurs to show that eccentric training translates into considerable gains in muscle mass and strength. Less is known, however, regarding its impact on oxygen transport and on factors to be considered for optimizing its prescription and monitoring. This article reviews the existing evidence for endurance eccentric exercise effects on the components of the oxygen transport system from systemic to mitochondria in both humans and animals. In the studies reviewed, specially designed cycle-ergometers or downhill treadmill running were used to generate eccentric contractions. Observations to date indicate that overall, the aerobic demand associated with the eccentric training load was too low to significantly increase peak maximal oxygen consumption. By extension, it can be inferred that the very high eccentric power output that would have been required to solicit a metabolic demand sufficient to enhance peak aerobic power could not be tolerated or sustained by participants. The impact of endurance eccentric training on peripheral flow distribution remains largely undocumented. Given the high damage susceptibility of eccentric exercise, the extent to which skeletal muscle oxygen utilization adaptations would be seen depends on the balance of adverse and positive signals on mitochondrial integrity. The article examines the protection provided by repeated bouts of acute eccentric exercise and reports on the impact of eccentric cycling and downhill running training programs on markers of mitochondrial function and of mitochondrial biogenesis using mostly from animal studies. The summary of findings does not reveal an impact of training on skeletal muscle mitochondrial respiration nor on selected mitochondrial messenger RNA transcripts. The implications of observations to date are discussed within future perspectives for advancing research on endurance eccentric exercise physiological impacts and using a combined eccentric and concentric exercise approach to optimize functional capacity.

Effect of Three Half-Squat Protocols on the Tensiomyographic Twitch Response and Tissue Damage of the Rectus Femoris and the Biceps Femoris

The aim of this study was to analyse the acute effects of a concentric exercise and two different eccentric overload exercises (EOEs) on blood markers of muscle damage (i.e. creatine kinase [CK], lactate dehydrogenase [LDH], myoglobin [Myo], and malondialdehyde [MDA]) and muscle contractile properties. Ten healthy, young (27 ± 1.5 years, 179 ± 6 cm, 78.7 ± 10.8 kg), physically active men (3.5 ± 1.9 h·w-1) randomly performed three training sessions using the following protocols: a half-squat (HS) as a concentric exercise, and exercises using Versapulley (VP) or YoYo isoinertial technology (YIT) as EOEs (4 x 7 repetitions with a 2 min rest interval between sets). Blood samples and tensiomyography measurements were obtained after each training session. Repeated measures analysis of variance (ANOVA) followed by the Tukey test was used to detect differences between the four time points of each variable. The standardized difference or effect size (ES, 90% confidence limit) in the selected variables was calculated using the basal SD. After all exercises, a greater activity of CK, LDH, and concentration of Myo, and MDA were found compared to baseline values (p < 0.05). A substantially greater activity of CK, LDH, and Myo concentration, but not MDA, were found after EOEs when compared to the HS protocol. Substantially lower tensiomyography results in the rectus femoris (RF) were reported, irrespective of the exercise mode performed. Also, no substantial differences were obtained in the biceps femoris (BF) between EOEs and the HS protocol. Time of contraction (Tc) in the RF was possibly to very likely lower in the HS in comparison to EOEs. Additionally, muscular displacement (Dm) in the RF was substantially lower in the HS compared to EOEs. VP produced higher concentrations of damage markers than YIT and concentric exercise did. Furthermore, tensiomyography variables showed similar activation in both exercises, although higher specific fatigue (in the RF) was registered in the traditional HS.

Morphology and Anabolic Response of Skeletal Muscles Subjected to Eccentrically or Concentrically Biased Exercise

Context Long-term eccentric exercise is known to promote muscle growth better than concentric exercise, but its acute effect on muscle is not well understood because of misinterpreted modeling and in situ and in vitro stretch protocols. Knowing if the initial bout of eccentric exercise promotes muscle growth and limits damage is critical to understanding the effect of this mode of exercise. Objective To directly evaluate the immediate effects of eccentric and concentric exercises on untrained muscle when fiber strains were physiological and exercise doses were comparable. Design Controlled laboratory study. Setting Laboratory. Patients or Other Participants A total of 40 skeletally mature male Long-Evans rats (age = 16 weeks, mass = 452.1 ± 35.2 g) were randomly assigned to an eccentric exercise (downhill walking, n = 16), concentric exercise (uphill walking, n = 16), or control (no exercise, n = 8) group. Intervention(s) Rats were exposed to a single 15-minute bout of eccentric or concentric exercise on a motorized treadmill and then were euthanized at 6 or 24 hours postexercise. We harvested the vastus lateralis muscle bilaterally. Main Outcome Measure(s) The percentage increase or decrease in protein abundance in exercised animals relative to that in unexercised control animals was evaluated as elevated phosphorylated p70S6k relative to total p70S6k. Fiber damage was quantified using immunoglobulin G permeability staining. One-way analysis of variance and post hoc Tukey tests were performed. Results Rats exposed to eccentric exercise and euthanized at 24 hours had higher percentage response protein synthesis rates than rats exposed to eccentric exercise and euthanized at 6 hours (P = .02) or to concentric exercise and euthanized at 6 (P = .03) or 24 (P = .03) hours. We assessed 9446 fibers for damage and found only 1 fiber was infiltrated (in the concentric exercise group euthanized at 6 hours). Furthermore, no between-groups differences in immunoglobulin G fluorescent intensity were detected (P = .94). Conclusions Incorporating eccentric exercise is a simple, universally available therapeutic intervention for promoting muscle recovery. A single 15-minute dose of eccentric exercise to a novice muscle can better exert an anabolic effect than a comparable dose of concentric exercise, with very limited evidence of fiber damage.

BIOMECHANICAL STUDY OF MUSCLE MOVEMENT IN THE PROCESS OF FOOTBALL TECHNICAL TRAINING

Study of biomechanical characteristics of muscles can provide an effective reference for the training of athletes. Football is a vigorous sport, and physical collision and damage are frequent during competition and training. In order to improve football skills and prevent sports injuries, 10 athletes from Sport College of Shaoyang University, Hunan, China, were tested for isokinetic muscle strength. The moment of flexors and extensors was measured when the flexion and extension angular speed of hip and knee joints was 50∘, 100∘, 150∘, 200∘, 250∘, 300∘, 350∘ and 400∘, respectively. Moreover the characteristics of force moment of flexor and extensor were verified by testing the electromyographic signal of the flexor and extensor of the hip and knee joints with isokinetic concentric exercise using piezoelectric sensor. The results showed that the electromyographic signal of the flexor and extensor of the hip and knee joint decreased with the increase of angular velocity of isokinetic concentric exercise; the electromyographic signal obtained by the piezoelectric sensor verified the law that the output of the flexor and extensor decreased, the extensor of the hip joint had incoordination during rapid movement, and the output of the extensor was always larger than that of the flexor no matter how fast the extensor moved.

Effectiveness of combined eccentric and concentric exercise over traditional cardiac exercise rehabilitation programme in patients with chronic heart failure: protocol for a randomised controlled study

IntroductionExercise-based rehabilitation is a standard feature of chronic heart failure management. The effectiveness of eccentric exercise could offer new opportunities for better tailoring rehabilitation programme to patients’ limitations. The goal of the study is to contrast the impact of a mixed eccentric and concentric cycling training programme, to that of conventional concentric cycling rehabilitation in patients with chronic heart failure (peak oxygen consumption (VO2Peak) < 15 mL⋅kg-1⋅min-1, ejection fraction <40%).Methods and analysisIt is a prospective, open, controlled and randomised study (2×25 subjects) carried out in a single centre. Subjects will perform five exercise sessions per week per the randomisation outcome, with the intervention group performing eccentric in three of the five weekly sessions while the control group will perform the five sessions of concentric exercise. Cycling intensity will be the same in both groups and fixed to the power associated with the first ventilatory threshold. Self-management education programme, callisthenics sessions and muscle strength trainings will also be carried out as for any heart failure patient normally included in the rehabilitation programme. The primary outcome will be the change in distance covered during the 6 min walk test. Secondary outcomes will include other physical mobility parameters, functional exercise capacities, quality of life and body composition as well as skeletal muscle properties including mitochondrial function parameters.Ethics and disseminationThe study has been approved by the institutional ethics review board (17.079) and the French regulatory authority for research (2017-A00969-44). Adverse events that could occur during the protocol will be reported to the principal investigator. The results will be published in an international peer-reviewed journal.Trial registration numberNCT03716778.