Effects of Descending Stair Walking on Health and Fitness of Elderly Obese Women

The effects of various stair-climbing exercises on functional mobility and trunk muscle activation in community-dwelling older adults: A pilot randomized controlled trial

BACKGROUND

Stair-climbing (SC) is an essential daily life skill, and stair-climbing exercise (SCE) serves as a valuable method for promoting physical activity in older adults. This study aimed to compare the impact of SCEs with heel contact (HC) and heel off (HO) during SC on functional mobility and trunk muscle (TM) activation amplitudes in community-dwelling older adults.

METHODS

In the pilot randomized controlled trial, participants were randomly allocated to either the HC group (n = 17; mean age 75.9 ± 6.3 years) or the HO group (n = 17; mean age 76.5 ± 4.6 years). The HC participants performed SCE with the heel of the ankle in contact with the ground, while the HO participants performed SCE with the heel of the ankle off the ground during SC. Both groups participated in progressive SCE for one hour per day, three days per week, over four consecutive weeks (totaling 12 sessions) at the community center. We measured timed stair-climbing (TSC), timed up and go (TUG), and electromyography (EMG) amplitudes of the TMs including rectus abdominis (RA), external oblique (EO), transverse abdominus and internal oblique abdominals (TrA-IO), and erector spinae (ES) during SC before and after the intervention.

RESULTS

Both groups showed a significant improvement in TSC and TUG after the intervention (P < .01, respectively), with no significant difference between the groups. There was no significant difference in the EMG activity of the TMs between the groups after the intervention. The amplitude of TMs significantly decreased after the intervention in both groups (P < .01, respectively).

CONCLUSION

Both SCE methods could improve balance and SC ability in older adults while reducing the recruitment of TMs during SC. Both SCE strategies are effective in improving functional mobility and promoting appropriate posture control during SC in older adults.

Effects of lunges inserted in walking (eccentric walking) on lower limb muscle strength, physical and cognitive function of regular walkers

INTRODUCTION

Walking is a popular exercise but does not increase lower limb muscle strength and balance. We hypothesized that muscle strength, physical and cognitive function would be improved by inserting lunges in conventional walking.

METHODS

Eleven regular walkers (54-88 years) who had more than 5000 steps in exercise walking a day at least 5 days a week participated in this study. They walked as usual for the first 4 weeks and included lunges and descending stairs or slope walking (i.e., eccentric walking) for the next 8 weeks. The steps of eccentric walking were gradually increased from 100 to 1000 steps per week over 8 weeks.

RESULTS

The average steps per day were 10,535 ± 3516 in the first 4 weeks, and 10,118 ± 3199 in the eccentric walking period without a significant difference. No significant changes in maximal voluntary isometric contraction torque of the knee extensors (MVC), 30-s chair stand (CS), 2-min step, balance assessed by center of pressure movement area with eyes close, sit and reach, a digit symbol substitution test (DSST) for cognitive function were observed in the first 4 weeks. However, significant (P < 0.05) improvements were evident in MVC (18.6 ± 15.7%), CS (24.2 ± 17.3%), balance ( - 45.3 ± 34.5%), and DSST (20.8 ± 16.7%) from weeks 4 to 12. Serum complement component 1q concentration decreased (P < 0.05) from weeks 4 to 12, although no changes in serum glucose, triglyceride, and cholesterol concentrations were observed.

CONCLUSION

These results supported the hypothesis, and suggest that eccentric walking provides effects that are not achieved by conventional walking.

Effects of acute and chronic stair-climbing exercise on metabolic health: A systematic review

Stair climbing exercise (SE) provides a feasible approach to elevate physical activity, but the effects on metabolic health are unclear. We systematically reviewed the currently available evidence on the effects of SE on fasting and postprandial glycaemia and lipidaemia. Studies were included if they investigated the effects of acute or chronic (at least 2 weeks) SE on fasting and/or postprandial glycaemic (insulin and glucose) and lipidaemic (triacylglycerols and non-esterified fatty acids) responses in healthy, prediabetic or type 2 diabetic adult populations. PubMed, Web of Science and Scopus were searched for eligible studies until July 2022. A total of 25 studies (14 acute and 11 chronic) were eligible for review. Acute bout(s) of SE can reduce postprandial glycaemia in individuals with prediabetes and type 2 diabetes (8 of 9 studies), but not in normoglycemic individuals. The effects of acute SE on postprandial lipidaemic responses and SE training on both fasting and postprandial glycaemia/lipidaemia were unclear. Acute SE may reduce postprandial glucose concentrations in people with impaired glycaemic control, but high-quality studies are needed. More studies are needed to determine the effect of chronic SE training on postprandial glucose and lipid responses, and the acute effects of SE on lipid responses.

Stair-climbing interventions on cardio-metabolic outcomes in adults: A scoping review

Objective

Physical inactivity is linked with high chronic disease risk; however, only a fraction of the global population meets the recommendations for physical activity. Stair-climbing is a simple and accessible form of physical activity that has been shown to improve cardio-metabolic outcomes in adults. The present scoping review explores the physiological and therapeutic effects of stair-climbing interventions on adult cardio-metabolic disease risk factors.

Methods

This scoping review followed the reporting guidelines of the Arksey & O'Malley framework, which collates evidence in stages. The research question was framed as "What are the effects of stair climbing on cardio-metabolic outcomes in adults?". Eligible articles were identified through an extensive search of four electronic databases, and data from 24 research studies were charted and organized.

Results

Stair climbing improves aerobic capacity (8-33 ml kg/min) and serum biomarkers by ≈9-15 %. A minimum of 4-8 weeks are necessary to alter cardiometabolic risk. Regular stair climbing can improve cardio-metabolic risk indicators, including body composition, blood pressure, cholesterol levels, and insulin sensitivity. The research regarding inflammatory and musculoskeletal changes with stair climbing bouts is still in its infancy.

Conclusion

Stair climbing interventions are a no-cost and feasible form of physical activity for improving cardiometabolic disease risk in adults.

Eccentric Muscle Actions Add Complexity to an Already Inconsistent Resistance Exercise Nomenclature

An eccentric muscle action (or contraction) is defined as active muscle lengthening against resistance, which occurs when the force generated by the muscle is smaller than the resistance placed upon it. Eccentric resistance exercise, which involves multiple sessions of repeated eccentric muscle actions, improves muscle strength and other health outcomes. In response to this evidence, new exercise technologies have been developed to permit feasible completion of eccentric muscle actions outside of the laboratory. Consequently, participation in eccentric resistance exercise is projected to increase in the future, and communications about eccentric resistance exercise are likely to reach a wide audience, including students in the classroom, athletes in the weightroom, patients who receive telehealth services,  and journalists who report on study findings. Previous research has documented inconsistencies in how resistance exercises are named, but the role of eccentric resistance exercises has not been considered. Here, we explain how eccentric resistance exercises add further complexity to an already inconsistent resistance exercise nomenclature. Specifically, action words in exercise names typically describe the movement that occurs in the concentric phase (e.g., "press", "raise", "curl", "pull", "row"). This naming bias likely stems from the fact that traditional resistance exercise equipment, such as free weights and weight stack machines, does not typically accommodate for greater eccentric than concentric strength and thus emphasizes the concentric over eccentric phase. This naming bias is likely to hinder communications about eccentric resistance exercise. Thus, we encourage researchers and practitioners to discuss ways in which resistance exercises can be named more clearly and consistently.

The acute and repeated bout effects of multi-joint eccentric exercise on physical function and balance in older adults

PURPOSE

Eccentric muscle actions generate high levels of force at a low metabolic cost, making them a suitable training modality to combat age-related neuromuscular decline. The temporary muscle soreness associated with high intensity eccentric contractions may explain their limited use in clinical exercise prescription, however any discomfort is often alleviated after the initial bout (repeated bout effect). Therefore, the aims of the present study were to examine the acute and repeated bout effects of eccentric contractions on neuromuscular factors associated with the risk of falling in older adults.

METHODS

Balance, functional ability [timed up-and-go and sit-to-stand], and lower-limb maximal and explosive strength were measured in 13 participants (67.6 ± 4.9 year) pre- and post-eccentric exercise (0, 24, 48, and 72 hr) in Bout 1 and 14 days later in Bout 2. The eccentric exercise intervention was performed on an isokinetic unilateral stepper ergometer at 50% of maximal eccentric strength at 18 step‧min-1 per limb for 7 min (126 steps per limb). Two-way repeated measures ANOVAs were conducted to identify any significant effects (P ≤ 0.05).

RESULTS

Eccentric strength significantly decreased (- 13%) in Bout 1 at 24 hr post-exercise; no significant reduction was observed at any other time-point after Bout 1. No significant reductions occurred in static balance or functional ability at any time-point in either bout.

CONCLUSION

Submaximal multi-joint eccentric exercise results in minimal disruption to neuromuscular function associated with falls in older adults after the initial bout.

Effect of Eccentric Exercise on Metabolic Health in Diabetes and Obesity

There is a growing body of evidence showing the importance of physical activity against civilization-induced metabolic diseases, including type 2 diabetes (T2DM) and obesity. Eccentric contraction, when skeletal muscles generate force by lengthening, is a unique type of skeletal muscle activity. Eccentric contraction may lead to better power production characteristics of the muscle because eccentric contraction requires less energy and can result in higher tension. Therefore, it is an ideal tool in the rehabilitation program of patients. However, the complex metabolic effect (i.e., fat mass reduction, increased lipid oxidation, improvement in blood lipid profile, and increased insulin sensitivity) of the eccentric contraction alone has scarcely been investigated. This paper aims to review the current literature to provide information on whether eccentric contraction can influence metabolic health and body composition in T2DM or obesity. We also discussed the potential role of myokines in mediating the effects of eccentric exercise. A better understanding of the mechanism of eccentric training and particularly their participation in the regulation of metabolic diseases may widen their possible therapeutic use and, thereby, may support the fight against the leading global risks for mortality in the world.

Skeletal effects of eccentric strengthening exercise: a scoping review

BACKGROUND

Conventional progressive concentric strengthening exercise (CSE) to improve bone mineral density (BMD) and bone mineral content (BMC) may not be feasible for populations with chronic musculoskeletal and/or metabolic conditions, such as osteoporosis or obesity. Muscle lengthening exercise, also known as an eccentric strengthening exercise (ESE), may have a special utility for those populations due to greater force generation versus CSE. In fact, greater mechanical loading can be induced on bone at lower resistance levels with ESE. However, effects of ESE on BMD and BMC are unclear. Thus, the purpose of this review was to interrogate the effects of ESE on BMD and BMC.

METHODS

A literature review was conducted between January 1995 and April 2022 focusing on randomized controlled trials investigating the effects of ESE on BMD and/or BMC in humans. Terms covering the domains of exercise, bone, and populations were searched on PubMed, CINAHL, and Scopus. The methodological quality of each interventional study was rated using Physiotherapy Evidence Database (PEDro) scale. Cohen's d was calculated to determine the magnitude of the effects of ERE on site-specific outcome measures of BMD and/or BMC.

RESULTS

Out of 1,182 articles initially found, a total of seven full length articles met our inclusion criteria. Of the seven studies, most of the interventions were performed in young (n = 5, PEDro = 5-7) versus middle-aged (n = 1, PEDro = 4) or older (n = 1, PEDro = 6) adults. BMD and BMC generally improved due to ESE; however the effects of ESE on BMD and BMC were non-homogenous. Effect size (d) ranged from 0.10-0.87 in young adults while it was 1.16 in older adults. Effect size (d) could not be calculated for the middle-aged adult study due to critical methodological limitations of the intervention.

CONCLUSIONS

Large variability exists for the effectiveness of ESE on BMD/BMC across the human life spectrum. The benefits of ESE on BMD holds promise but rigorous studies are lacking. Further research is needed to examine if the dose, mode, age, and sex-specificity dictate effects of ESE on BMD/BMC.

Connective Adaptive Resistance Exercise (CARE) Machines for Accentuated Eccentric and Eccentric-Only Exercise: Introduction to an Emerging Concept

Eccentric resistance exercise emphasizes active muscle lengthening against resistance. In the past 15 years, researchers and practitioners have expressed considerable interest in accentuated eccentric (i.e., eccentric overload) and eccentric-only resistance exercise as strategies for enhancing performance and preventing and rehabilitating injuries. However, delivery of eccentric resistance exercise has been challenging because of equipment limitations. Previously, we briefly introduced the concept of connected adaptive resistance exercise (CARE)-the integration of software and hardware to provide a resistance that adjusts in real time and in response to the individual's volitional force within and between repetitions. The aim of the current paper is to expand this discussion and explain the potential for CARE technology to improve the delivery of eccentric resistance exercise in various settings. First, we overview existing resistance exercise equipment and highlight its limitations for delivering eccentric resistance exercise. Second, we describe CARE and explain how it can accomplish accentuated eccentric and eccentric-only resistance exercise in a new way. We supplement this discussion with preliminary data collected with CARE technology in laboratory and non-laboratory environments. Finally, we discuss the potential for CARE technology to deliver eccentric resistance exercise for various purposes, e.g., research studies, rehabilitation programs, and home-based or telehealth interventions. Overall, CARE technology appears to permit completion of eccentric resistance exercise feasibly in both laboratory and non-laboratory environments and thus has implications for researchers and practitioners in the fields of sports medicine, physiotherapy, exercise physiology, and strength and conditioning. Nevertheless, formal investigations into the impact of CARE technology on participation in eccentric resistance exercise and clinical outcomes are still required.

The Health and Functional Benefits of Eccentric versus Concentric Exercise Training: A Systematic Review and Meta-Analysis

This review compared the effects of eccentric versus concentric exercise training in healthy people and people with metabolic disease. A systematic search on Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, SPORTDiscus, Web of Science, SCOPUS and PubMed was conducted in February 2022. Randomised controlled trials conducted on sedentary healthy adults or those with an existing metabolic disease that compared eccentric versus concentric exercise training interventions of four weeks or longer that involved multiple joints and large muscle groups (e.g., walking, whole-body resistance training) were included in the review. The primary outcome was glucose handling, measured as HbA1c, HOMA, fasting glucose or insulin. Measures of cardiovascular health, muscle strength, and functional physical fitness were secondary outcomes. Nineteen trials involving 618 people were included. Results of meta-analyses showed that eccentric exercise had no benefit to glucose handling (HbA1c level; SMD - 0.99; 95% CI, -2.96 to 0.98; n = 74; P = 0.32) but resulted in significant increases in overall muscle strength (SMD 0.70; 95% CI 0.25 to 1.15; n = 224; P = 0.003) and decreases in blood pressure (Systolic Blood Pressure; MD -6.84; 95% CI, -9.84 to -3.84; n = 47, P = 0.00001, and Diastolic Blood Pressure; MD -6.39; 95% CI -9.62 to -3.15; n = 47, P = 0.0001). Eccentric exercise is effective for improving strength and some markers of cardiovascular health compared to traditional exercise modalities. Additional high-quality studies are necessary to validate these results. (PROSPERO registration: CRD42021232167).

Assessing Handrail-Use Behavior during Stair Ascent or Descent Using Ambient Sensing Technology

The increasing geriatric population across the world has necessitated the early detection of frailty through the analysis of daily-life behavioral patterns. This paper presents a system for ambient, automatic, and the continuous measurement and analysis of ascent and descent motions and long-term handrail-use behaviors of participants in their homes using an RGB-D camera. The system automatically stores information regarding the environment and three-dimensional skeletal coordinates of the participant only when they appear within the camera's angle of view. Daily stair ascent and descent motions were measured in two houses: one house with two participants in their 20s and two in their 50s, and another with two participants in their 70s. The recorded behaviors were analyzed in terms of the stair ascent/descent speed, handrail grasping points, and frequency determined using the decision tree algorithm. The participants in their 70s exhibited a decreased stair ascent/descent speed compared to other participants; those in their 50s and 70s exhibited increased handrail usage area and frequency. The outcomes of the study indicate the system's ability to accurately detect a decline in physical function through the continuous measurement of daily stair ascent and descent motions.

Changes in Blood Markers of Oxidative Stress, Inflammation and Cardiometabolic Patients with COPD after Eccentric and Concentric Cycling Training

Chronic obstructive pulmonary disease (COPD) patients manifest muscle dysfunction and impaired muscle oxidative capacity, which result in reduced exercise capacity and poor health status. This study examined the effects of 12-week eccentric (ECC) and concentric (CONC) cycling training on plasma markers of cardiometabolic health, oxidative stress, and inflammation in COPD patients. A randomized trial in which moderate COPD was allocated to ECC (n = 10; 68.2 ± 10.0 year) or CONC (n = 10; 71.1 ± 10.3 year) training groups. Participants performed 12-week ECC or CONC training, 2-3 sessions per week, 10 to 30 min per session. Before and after training, peak oxygen consumption, maximal power output (VO_2peak and PO_max), and time-to-exhaustion (TTE) tests were performed. Plasma antioxidant and oxidative markers, insulin resistance, lipid profile, and systemic inflammation markers were measured before and after training at rest. VO_2peak, PO_max and TTE remained unchanged after ECC and CONC. CONC induced an increase in antioxidants (p = 0.01), while ECC decreased antioxidant (p = 0.02) markers measured at rest. CONC induced lesser increase in oxidative stress following TTE (p = 0.04), and a decrease in insulin resistance (p = 0.0006) compared to baseline. These results suggest that CONC training induced an increase in insulin sensitivity, antioxidant capacity at rest, and lesser exercise-induced oxidative stress in patients with moderate COPD.

Eccentric exercise improves myocardial oxygen supply/demand balance with decelerating aortic diastolic pressure decay: The acute and chronic studies

Both eccentric (ECC) and concentric (CON) exercises improve energy expenditure and blood lipid profile. Although ECC exercise has a more beneficial effect on these factors than CON exercise, its benefits on vital organs are still unclear. This study investigated the mode-of-action-dependent effects on myocardial perfusion index. Seventeen healthy men (age: 26 ± 5 years) were randomly enrolled in CON (n = 9) and ECC (n = 8) groups. Transient exercise and regular training (three-day a week for 4-week) included bicep curl comprising 5-set of 10-repetition, each using 75% one-repetition maximum concentric loading. The ECC group performed one-repetition of ECC for 3-s and CON for 1-s, while the CON group performed one-repetition of CON for 3-s and ECC for 1-s. All participants were assessed for subendocardial viability ratio (SEVR, myocardial perfusion index) and aortic diastolic pressure decay. Before study, these were found to be same for both groups. Transient (ΔSEVR: 20.3 ± 13.3%, p = 0.01; Δdecay: -0.07 ± 0.02 s^-1, p < .001) and regular (ΔSEVR: 18.5 ± 12.8%, p = .001; Δdecay: -0.06 ± 0.05 s^-1, p = .004) ECC (but not CON) exercises significantly increased SEVR and decelerated decay. Increased SEVR with ECC exercise was associated with decelerated decay (transient ECC: r² = 0.56, 95% confidence interval [CI] = -0.95 to -0.10, p = .03; regular ECC: r² = 0.53, 95% CI = -0.95 to -0.05, p = .04). These findings suggest that ECC exercise improves myocardial perfusion and diastolic pressure contour is involved in physiological mechanisms.

Desk based prompts to replace workplace sitting with stair climbing; a pilot study of acceptability, effects on behaviour and disease risk factors

Background

Prolonged sitting is associated with increased risk of obesity, type 2 diabetes and cardiovascular disease. Occupational sitting accounts for up to 50 h/week for employees. This pilot study assessed the acceptability of stair climbing as an interruption to sitting throughout working hours, and provided preliminary data of the effects on glucose and lipid profiles.

Methods

A quasi-experimental design was conducted involving 16 sedentary office workers (five females and 11 males) for intervention (n = 8) and control groups (n = 8) with mean age of 36.38 (5.58). For the eight-week intervention, a continuous four-floor stair climb and descent was performed eight times/day spread evenly over the working day. A prompt to climb was presented on the participant’s computer eight times/day. Participants in the experimental group recorded daily floors climbed and steps (measured using pedometers) in a weekly log sheet. Blood samples were collected pre and post intervention to test effects on fasting glucose and 2 h plasma glucose, triglycerides, and total (TC), LDL and HDL cholesterol. Experimental participants were interviewed at the end of the study. The Wilcoxon signed rank test was used to compare the median changes (pre-post) of the dependent variables.

Results

On average, the experimental group climbed 121 floors/week when prompted. There were significant reductions in fasting blood glucose, TC and LDL, as well as the derived measures of ‘bad’ cholesterol and the TC/HDL ratio in the experimental group. Post-experimental interviews indicated that the interruption to sitting was well tolerated.

Conclusion

Prompted stair climbing activity had impacts on health outcomes and was found acceptable to employees at work.

Trial registration

Ethics for this study was approved by Science, Technology, Engineering and Mathematics Ethical Review Committee, University of Birmingham with ethics reference number ERN_15_0491.

Supplementary information

The online version contains supplementary material available at 10.1186/s12889-022-14393-1.

Changes in Insulin Sensitivity and Lipid Profile Markers Following Initial and Secondary Bouts of Multiple Eccentric Exercises

An acute bout of eccentric exercise affects insulin sensitivity and lipid profile, but how the magnitude of muscle damage affects them is not clear. We compared changes in blood insulin sensitivity and lipid markers after the first (EC1) and second (EC2) eccentric exercise bouts. Fifteen sedentary young men performed arm, leg and trunk muscle eccentric exercises, and repeated them 2 weeks later. Fasting blood samples were taken before, 2 h and 1–5 days after each exercise bout to analyze plasma creatine kinase (CK) activity, serum glucose (GLU), insulin, homeostasis model assessment (HOMA), triacylglycerols (TG), total (TC) and low- (LDLC) and high-density lipoprotein cholesterol (HDLC) concentrations as well as TC/HDLC ratio. Changes in these measures were compared between bouts and relationships to peak plasma CK activity were analyzed. Plasma CK activity increased (p < 0.05) after EC1 (peak: 101,668 ± 58,955 IU/L) but not after EC2. The magnitude of changes in GLU (peak after EC1: 26 ± 10% vs. EC2: 7 ± 6%), insulin (46 ± 27% vs. 15 ± 8%), HOMA (86 ± 48% vs. 24 ± 15%), TC (−20 ± 5% vs. −6 ± 4%), TG (−32 ± 11% vs. −6 ± 3%), LDHC (−47 ± 15% vs. −12 ± 9%), HDLC (35 ± 26% vs. 7 ± 4%), and TC/HDLC ratio (−139 ± 13% vs. −11 ± 7%) were significantly greater after EC1 than EC2. Peak plasma CK activity was significantly (p < 0.05) correlated with the peak changes in blood insulin sensitivity and lipid markers for the combined data of EC1 and EC2. These results suggest that the greater the magnitude of muscle damage, the greater the magnitude of changes in the insulin sensitivity to a negative direction and lipid markers to a positive direction.

A Short-Term Eccentric HIIT Induced Greater Reduction in Cardio-Metabolic Risk Markers in Comparison With Concentric HIIT in Sedentary Overweight Men

Background: Steady-state eccentric exercise training improves cardiometabolic risk (CMR) despite lesser cardiovascular demands compared with load-matched concentric training. Whether a high-intensity interval eccentric training is also effective reducing CMR is unknown. Aim: To compare the effects of a short-term high-intensity interval eccentric training (ECC-HIIT) with high-intensity interval concentric training (CONC-HIIT) on CMR in sedentary overweight men. Methods: Twenty men (age: 27.9 ± 5.3y, body massindex: 29.1 ± 3.1 kg·m-2) were randomly assigned to ECC-HIIT (n = 10) or CONC-HIIT (n = 10) delivered as six sessions, including 4 x 5:2 min work-to-rest ratio, at 80% peak concentric power output. Heart rate (HR), rate of perceived exertion (RPE) and muscle soreness weremonitored during training sessions. Training effects on lipid profile, insulin sensitivity (HOMA-IR), body composition, thigh circumference, isometric knee extensors maximal strength, resting systolic and diastolic blood pressure (SBP and DBP) were determined. Results: Average training HR and RPE were -29%and -50%lower in ECC-HIIT in comparison with CONC-HIIT. Muscle soreness was initially greater after ECC-HIIT compared with CONC-HIIT. Significant changes in total and low-density lipoprotein cholesterol (-7.0 ± 8.7%; p = .02 and -6.3 ± 14.4%; p = .03), SBP (-9.8 ± 7.8%; p = .002), and maximal thigh circumference (+2.5 ± 3.1%; p = .02) were observed following ECC-HIIT. No changes in any CMR marker were observed after CONC-HIIT. Moderate-to-large training effect sizes were obtained in thigh circumference, SBP, total cholesterol and low-density lipoprotein cholesterol in response to ECC-HIIT. Conclusion: A two-week ECC-HIIT was well-tolerated and induced rapid onset improvements in cholesterol and blood pressure compared to conventional CONC-HIIT in sedentary overweight men.

The Effect of Eccentric vs. Traditional Resistance Exercise on Muscle Strength, Body Composition, and Functional Performance in Older Adults: A Systematic Review With Meta-Analysis

The effects of eccentric exercise (ECC) in older adults have received limited scientific attention, considering the ample evidence for its effectiveness in general and athletic populations. The purpose of this paper is to review the effects of ECC exercise modalities vs. traditional or concentric (CON) exercise on muscle strength, body composition and functional performance in older adults. Inclusion criteria regarding the age was >55 years. Three major scientific literature databases (PubMed, Scopus and Web of Science) were screened for trials comparing the effect of ECC and CON exercise programs, and 19 papers were included in the meta-analysis. ECC and CON training programs were typically matched by the duration of each session. The difference between ECC and CON was expressed as standardized mean difference (SMD). Regarding isometric knee strength, the pooled effect favored ECC (SMD = 0.50), but was not statistically significant (p = 0.160). ECC exercise elicited greater improvements in timed up and go test (SMD = −0.68; p = 0.004), 2-min sit-stand test (SMD = 0.53; p = 0.030) and 30-s sit-stand test (SMD = 0.81; p = 0.002), but not in 6-min walking test (SMD = 0.01; p = 0.960). The effects on body composition and muscle architecture were unclear (SMD = −1.44 to 1.95; p = 0.060–0.689). In conclusion, our literature review indicates that ECC exercise is superior to, or at least as good as CON exercise for preserving health and overall function in older adults.

Feasability of An Eccentric Isokinetic Protocol to Induce Trunk Muscle Damage: A Pilot Study

Eccentric exercise is discussed as a treatment option for clinical populations, but specific responses in terms of muscle damage and systemic inflammation after repeated loading of large muscle groups have not been conclusively characterized. Therefore, this study tested the feasibility of an isokinetic protocol for repeated maximum eccentric loading of the trunk muscles. Nine asymptomatic participants (5 f/4 m; 34±6 yrs; 175±13 cm; 76±17 kg) performed three isokinetic 2-minute all-out trunk strength tests (1x concentric (CON), 2x eccentric (ECC1, ECC2), 2 weeks apart; flexion/extension, 60°/s, ROM 55°). Outcomes were peak torque, torque decline, total work, and indicators of muscle damage and inflammation (over 168 h). Statistics were done using the Friedman test (Dunn’s post-test). For ECC1 and ECC2, peak torque and total work were increased and torque decline reduced compared to CON. Repeated ECC bouts yielded unaltered torque and work outcomes. Muscle damage markers were highest after ECC1 (soreness 48 h, creatine kinase 72 h; p<0.05). Their overall responses (area under the curve) were abolished post-ECC2 compared to post-ECC1 (p<0.05). Interleukin-6 was higher post-ECC1 than CON, and attenuated post-ECC2 (p>0.05). Interleukin-10 and tumor necrosis factor-α were not detectable. All markers showed high inter-individual variability. The protocol was feasible to induce muscle damage indicators after exercising a large muscle group, but the pilot results indicated only weak systemic inflammatory responses in asymptomatic adults.

Exercise medicine for cancer cachexia: targeted exercise to counteract mechanisms and treatment side effects

Purpose

Cancer-induced muscle wasting (i.e., cancer cachexia, CC) is a common and devastating syndrome that results in the death of more than 1 in 5 patients. Although primarily a result of elevated inflammation, there are multiple mechanisms that complement and amplify one another. Research on the use of exercise to manage CC is still limited, while exercise for CC management has been recently discouraged. Moreover, there is a lack of understanding that exercise is not a single medicine, but mode, type, dosage, and timing (exercise prescription) have distinct health outcomes. The purpose of this review was to examine the effects of these modes and subtypes to identify the most optimal form and dosage of exercise therapy specific to each underlying mechanism of CC.

Methods

The relevant literatures from MEDLINE and Scopus databases were examined.

Results

Exercise can counteract the most prominent mechanisms and signs of CC including muscle wasting, increased protein turnover, systemic inflammation, reduced appetite and anorexia, increased energy expenditure and fat wasting, insulin resistance, metabolic dysregulation, gut dysbiosis, hypogonadism, impaired oxidative capacity, mitochondrial dysfunction, and cancer treatments side-effects. There are different modes of exercise, and each mode has different sub-types that induce vastly diverse changes when performed over multiple sessions. Choosing suboptimal exercise modes, types, or dosages can be counterproductive and could further contribute to the mechanisms of CC without impacting muscle growth.

Conclusion

Available evidence shows that patients with CC can safely undertake higher-intensity resistance exercise programs, and benefit from increases in body mass and muscle mass.

Changes in blood bone markers after the first and second bouts of whole-body eccentric exercises

The present study compared the first (EC1) and second (EC2) bouts of whole-body eccentric exercises to examine the effects of the magnitude of muscle damage on changes in blood bone markers. Fifteen sedentary young men performed nine eccentric exercises of arm, leg and trunk muscles, and repeated them two weeks later. Blood samples were taken before and two hours and one to five days following each bout to analyze plasma creatine kinase (CK) activity and myoglobin concentration, serum tartrate resistant acid phosphatase (TRAP), type 1 C-terminal telopeptide (CTX-1), procollagen type I N-terminal propeptide (P1NP), bone-specific alkaline phosphatase (BAP), undercarboxylated-osteocalcin (ucOCN), carboxylated-osteocalcin (cOCN), and leptin concentrations. All except ucOCN changed significantly (P<0.05) after both bouts. When comparing bouts for peak changes, P1NP (bone formation marker) and CTX-1 (bone resorption marker) increased less after EC2 (peak: 137±96% and 7±6%, respectively) than after EC1 (146±80% and 30±21%, respectively), whereas BAP (bone formation marker) increased more after EC2 (18±16%) than after EC1 (4±15%) (P<0.05). Leptin (49±58%) and cOCN (14±10%) increased more (P<0.05) after EC2 than after EC1 (-30±15%, 9±26%). Significant (P<0.05) correlations were evident between peak CK activity and peak CTX-1 (r=0.847), P1NP (r=0.815), BAP (r=-0.707), ucOCN (r=0.627), cCON (r=-0.759) and leptin (r=-0.740) changes after EC1, but many of these correlations disappeared after EC2. This was also found for the relationships between other muscle damage markers (myoglobin, muscle soreness and muscle strength) and the bone markers. It was concluded that bone turnover was affected by eccentric exercise, but muscle damage was unfavorable for bone formation.

Effects of an Eccentric Training Protocol Using Gliding Discs on Balance and Lower Body Strength in Healthy Adults

Impaired balance and lower body weakness are the main causes of falls, which are considered to be the major cause of fractures and head injuries in the elderly and are recognised as a serious health problem. The aim of this study is to observe the effect of eccentric training, introducing new technologies (gliding discs), on body composition, lower body strength, balance and quality of life. A quasi-experimental study was carried out with 56 healthy participants who were divided into an experimental group (n = 31) who underwent the protocol consisting of 12 training sessions and a control group (n = 25) who did not undergo the training. Before and after the intervention, all participants underwent a measurement of body composition, the SJ jump, balance with accelerometry and quality of life with the Short Form 12 Health Survey. In the experimental group, statistically significant improvements were found in the variables balance and lower body strength. The application of this training protocol improves lower body strength and the ability to control balance in the adult population.

Thirty minutes of moderate-intensity downhill or level running has no effect on postprandial lipemia: A randomized controlled trial

Elevated postprandial triglyceride (TG) concentrations are linked to a relatively high risk of cardiovascular disease. Eccentric endurance exercise, such as downhill walking and running, can provide metabolic benefits similar to concentric exercise. However, whether eccentric exercise affects postprandial lipemia remains unknown. Nine healthy young men performed level running (trial) or downhill running (DR trial, -15% slope) at 60% [INSIDE:1]O_2max or rest (CON trial) for 30 min in a randomized crossover design. The participants were fed a high-fat meal the next day. Blood and expired gas samples were collected before and 0.5, 1, 2, 3, 4, 5, and 6 h after the meal. Muscle soreness was measured using a visual analog scale. The DR trial induced mild muscle damage. During the 6-h postprandial period, serum TG concentrations and area under the curve (AUC) were similar across the three trials. The DR trial had a significantly higher AUC of nonesterified fatty acid concentrations and a significantly lower AUC of glucose concentrations than the CON trial. The results suggested that neither moderate-intensity DR nor running a level surface had a significant effect on lipemia after a high-fat meal. However, DR improved the postprandial glycemic response.

Influence of COVID-19 Building Restrictions on Physical Activity Promotion Through Increased Stair Use and Limited Elevator Access: A Quasi-Experimental Study-Sport and Physical Activity Group Active Campus Project

BACKGROUND

The aim of this study was to determine the effectiveness of UK government COVID-19 safe offices policy to increase stair use in a higher education setting during the COVID-19 pandemic.

METHODS

Automated counts at 3 ground floor staircases and the elevator entrances were used to estimate stair to elevator use ratio for ascent and descent from/to the ground floor of a university building at baseline (January to March 2020), first and second intervention months (October 2020, November 2020, respectively). Stair promoting signage and a 1-way system was implemented, in line with government policy.

RESULTS

At baseline, stair to elevator use ratio for ascent from and descent to the ground floor was 1.36 (0.02) and 1.88 (0.02) people, respectively. The ratio significantly increased in the first intervention month to 2.64 (0.09) and 3.96 (0.22) people for ascent and descent, respectively. However, the ratio decreased between the first and second intervention months to 1.63 (0.06) and 3.05 (0.52) people for ascent and descent, respectively.

CONCLUSION

The UK government COVID-19 policy was effective at increasing stair use in a higher education setting.

Changes in plasma C1q, apelin and adropin concentrations in older adults after descending and ascending stair walking intervention

This study compared changes in plasma complement component 1q (C1q), apelin and adropin concentrations in older obese women after descending (DSW) and ascending stair walking (ASW) training (n = 15/group) performed twice a week for 12 weeks, with gradual increases in exercise time from 5 to 60 min. Fasting blood samples were collected 3 days before the first and 4 days after the last training session. The improvements in the maximal voluntary isometric contraction (MVIC) strength of the knee extensors, functional physical fitness [e.g., 30-s chair stand (CS) performance], resting systolic blood pressure (SBP), insulin sensitivity [e.g., oral glucose tolerance test (OGTT)] and blood lipid profiles [e.g., total cholesterol (TC)] were greater (p < 0.05) in the DSW than ASW group. Plasma C1q decreased (− 51 ± 30%), and apelin (23 ± 15%) and adropin (127 ± 106%) increased (p ≤ .0.05) only after DSW. Significant (p ≤  0.01) partial correlations were found between the pre- to post-DSW changes in C1q, apelin or adropin and changes in outcome measures [e.g., C1q and MVIC (r = − 0.837), apelin and SBP (r = − 0.854), and andropin and OGTT (r = − 0.729)]. These results showed that greater decreases in plasma C1q and greater increases in apelin and adropin concentrations were associated with greater improvements in outcome measures after DSW than after ASW.

Downhill hiking improves low-grade inflammation, triglycerides, body weight and glucose tolerance

Exercise is a well-established tool for cardiovascular risk reduction. Particularly eccentric exercise, which essentially means walking downwards could favour more people becoming physically active. With the present controlled study, we tested the hypothesis that eccentric exercise can improve insulin sensitivity, triglyceride handling, body mass index, glucose tolerance and inflammation. We allocated 127 healthy sedentary individuals to one of two groups: (i) an active group of 102 individuals walking downwards a predefined route three to five times per week over two months, covering a difference in altitude of 540 m; for the upward route a cable car was used, for which adherence was recorded electronically and (ii) a matched control group of 25 individuals who stayed sedentary. Fasting and postprandial metabolic profiles were obtained at baseline and after two months. Compared to baseline, eccentric exercise significantly improved HOMA insulin resistance (1.94 ± 1.65 vs. 1.71 ± 1.36 (µU⁻¹ ml) × ((mmol/l)⁻¹22.5); p = 0.038) and resulted in a decrease in fasting glucose (97 ± 15 vs. 94 ± 9 mg dl⁻¹; p = 0.025) and glucose tolerance (238 ± 50 vs. 217 ± 47 mg dl⁻¹ h⁻¹; p < 0.001), whereas these parameters did not change significantly in the control group. Eccentric exercise significantly improved triglyceride tolerance (1923 ± 1295 vs. 1670 ± 1085 mg dl⁻¹ h⁻¹; p = 0.003), whereas triglyceride tolerance remained unchanged in the control group (p = 0.819). Furthermore, body mass index (27.7 ± 4.3 vs. 27.4 ± 4.3 kg m⁻²; p = 0.003) and C-reactive protein (0.27 ± 0.42 vs. 0.23 ± 0.25 mg dl⁻¹; p = 0.031) were significantly lowered in the eccentric exercise group but not in the control group. Downhill walking, a type of exercise is a promising unusual exercise modality with favorable effects on body mass index, insulin action, on postprandial glucose and triglyceride handling and on C-reactive protein.

ClinicalTrials.gov Identifier: NCT00386854.

Effects of volume-matched resistance training with different loads on glycemic control, inflammation, and body composition in prediabetic older adults

The purpose of the investigation was to examine the influence of resistance training (RT) with equal volume and varying load on glycemic control, inflammation, and body composition in non-obese prediabetic older adults. Non-obese older adults with prediabetes were randomized into two groups - high-load (80% 1RM) and low-load (40% of 1RM) RT (n=12/group), both with the same training volume. Oral glucose tolerance test (OGTT) and blood samples were collected at baseline and again after 10 weeks of RT. Fasting plasma glucose (103.8 vs. 99.9 mg/dL) and the area under the curve (AUC) of OGTT (0-30min) decreased significantly in older adults with prediabetes after 10-weeks of volume-matched RT (p < 0.05). Serum levels of MCP-1 (138.7 vs. 98.5 pg/mL) and TNF-α (1.8 vs. 1.3 pg/mL) showed significant decrease after 10-weeks of high-load RT (p < 0.05). There were no changes in IL-10, IL-6, and CRP levels in both groups. Leptin showed significant decrease after 10-weeks of low-load RT (p < 0.05). Changes in fasting glucose and AUC of OGTT (0-120 min) were positively correlated with changes in MCP-1 and TNF-α (p < 0.05). Lean body mass (39.6 vs. 40.3 kg) increased significantly after 10-weeks of volume-matched RT (p < 0.05). Results indicate that equal-volume RT at different loads is beneficial to glycemic control and muscle growth, and high-load RT shows more prominent anti-inflammatory effects. Novelty: ●Short-term high-load resistance training can help older adults bring their blood sugar level back to normal. ●High-load resistance training attenuates aging-associated chronic inflammation.

Down stair walking: A simple method to increase muscle mass and performance in 65+ year healthy people

Exercise is important for prevention of sarcopenia in the elderly population. We tested two training modalities, ascending or descending stair walking, representing concentric (CON) and eccentric (ECC) exercise, respectively. We also tested the effects of additional weight during eccentric exercise (ECC+). Thirty-two healthy men and women (70 ± 3 [mean ± SE] yrs.) were randomly assigned to CON, ECC, or ECC+ (carrying +15% of body weight in a vest) in a 3 (n = 32) or 6 (n = 21) week intervention (3 sessions/week). Data was analysed by mixed models approach. Rate of perceived exertion (RPE; Borg scale 6-20; mean values from 3 and 6 weeks) during training did not differ between CON (12.3 ± 0.4), ECC (11.5 ± 0.3), and ECC+ (11.7 ± 0.4). After 6 weeks, leg muscle mass increased more in ECC+ (+0.29 ± 0.09 kg) vs CON (+0.08 ± 0.05 kg) (P<0.05) but not different from ECC (+0.16 ± 0.06 kg). 6-minute walk test (6MWT) increased after 6 weeks more (P<0.05) in ECC+ (+85 ± 23 m) compared with ECC (+37 ± 13 m) and CON (+27 ± 12 m). Intramyocellular glycogen content increased from 359 ± 19 nmol/mg d.w. in CON (to 511 ± 65 and 471 ± 44 after 3 and 6 wks, respectfully (P<0.05)), but not in ECC (to 344 ± 28 after 6 weeks) or in ECC+ (to 389 ± 20 after 6 weeks). Conclusion: carrying extra weight while descending stair walking do not increase RPE, but the ECC+ training resulted in greater muscle responses compared with CON, but glycogen synthesis was stimulated only in CON. Descending stairs is a simple model for prevention and treatment of sarcopenia and the stimulus is enhanced by carrying extra weights.

Striking muscle adaptations induced by volume-dependent repeated bouts of low-intensity eccentric exercise of the elbow flexors

We investigated the effects of repeating 30 low-intensity eccentric contractions with a dumbbell corresponding to 10% maximal isometric strength (10%EC) on muscle strength and hypertrophy, and muscle damage after 30 maximal eccentric contractions (MaxEC) of the elbow flexors. Young men were placed into 1 of 3 experimental groups that performed 10%EC either once, twice a week for 4 (8 bouts) or 8 weeks (16 bouts) before MaxEC, or a control group that performed 2 bouts of MaxEC separated by 2 weeks (n = 13/group). Repeating 16 bouts of 10%EC increased (P < 0.05) maximal voluntary contraction strength (30 ± 21%) and muscle thickness (4.2 ± 2.3%) greater than 8 bouts (16 ± 4%, 1.9 ± 1.3%). Changes in the muscle damage markers after MaxEC were smaller (P < 0.05) for the experimental groups than the control group, and the magnitude of muscle damage protection was greater (P < 0.05) after 16 bouts (65 ± 30%) than 8 bouts (55 ± 33%), followed by 1 bout (34 ± 27%). The protection by 16 bouts was similar (P = 0.81) to that shown by the second MaxEC of the control group. These results showed that 10%EC produced potent muscle adaptation effects accumulatively and conferred muscle damage protection, but 1 bout of 10%EC was still effective for conferring approximately 20% of the protection of that by 16 bouts. Novelty: Repeating low-intensity eccentric exercise induces large increases in muscle strength and hypertrophy. Low-intensity eccentric exercise protects muscle damage induced by maximal eccentric contractions, and the protection is reinforced by repeating it. These are especially beneficial for individuals who are frail and cannot tolerate high-intensity resistance training.

Elevated body temperature contributes to the increased heart rate response during eccentric compared to concentric cycling when matched for oxygen consumption

A cardiovascular requirement to facilitate thermal homeostasis may partly contribute to the elevated heart rate during eccentric cycling. This study compared the body temperature response to a bout of eccentric (ECC) and concentric (CON) cycling to account for the difference in heart rate. Eight (N = 8) aerobically trained males (age 35 y [SD 8], peak oxygen consumption 3.82 L.min^-1 [SD 0.79]) completed an ECC cycling trial (60% PPO) followed by an oxygen consumption/duration matched CON trial (30   ∘ C , 35% RH) on a separate day. Trial termination was determined as an elevation in aural temperature, a surrogate of deep body temperature, by +0.5   ∘ C during ECC. Mean skin (8-sites) and body temperature (weighting of 80:20 for auditory canal and mean skin temperature) were calculated. Matching the oxygen consumption between the trials increased external work during ECC cycling (CON: 71 [SD 14] ECC: 194 [SD 38] W, p < 0.05) and elevated aural temperature (+0.5   ∘ C ) by 20 min 32 s [SD 9 min 19 s] in that trial. The peak rate of rise in aural temperature was significantly greater in ECC (CON: 0.012 [SD 0.007] ECC: 0.031 [SD 0.002] ^oC.s^-1, p < 0.05). Aural, mean skin and body temperature were significantly higher during the ECC trial (p < 0.05) and this was accompanied by elevated mean heart rate (CON: 103 [SD 14] ECC: 118 [SD 12] b.min^-1, p < 0.05) and thermal discomfort (p < 0.05). Moderate load eccentric cycling imposes an elevated thermal strain when compared to concentric cycling. This requirement for dissipating heat, in part, explains the elevated heart rate during eccentric cycling.

Home-Based Stair Climbing as an Intervention for Disease Risk in Adult Females; A Controlled Study

Cardiovascular disease and the metabolic syndrome are major contributors to health care expenditure. Increased physical activity reduces disease risk. The study compared effects of walking up and down stairs at home with continuous, gym-based stair climbing on the disease risk factors of aerobic fitness, serum lipids, body composition, fasting blood glucose, and resting cardiovascular variables. Sedentary women (31.7 ± 1.4 years) were randomly assigned to home-based (n = 26) or gym-based (n = 24) climbing for five days.week⁻¹ over an eight-week period. Each ascent required a 32.8-m climb, with home-based climbing matching the vertical displacement in the gym. Participants progressed from two ascents.day⁻¹ to five ascents.day⁻¹ in weeks 7 and 8. Relative to controls, stair climbing improved aerobic fitness (V˙O₂max +1.63 mL.min⁻¹.kg⁻¹, 95% CI = 1.21–2.05), body composition (weight −0.99 kg, 95% CI = 1.38–0.60), and serum lipids (LDL cholesterol −0.20 mmol.L⁻¹, 95% CI = 0.09–0.31; triglycerides −0.21 mmol.L⁻¹, 95% CI = 0.15–0.27), with similar risk reductions for home and gym-based groups. Only the home-based protocol reduced fasting blood glucose. Discussion focuses on stair climbing bouts as time-efficient exercise and the potential benefits of a home-based intervention. Stair use at home offers a low-cost intervention for disease risk reduction to public health.

Effect of preconditioning exercise on biceps brachii myotendinous junction displacement during elbow flexor eccentric exercise

The present study tested the hypothesis that 30 low-intensity (10%) eccentric contractions (10%EC) or two maximal voluntary isometric contractions at a long muscle length (2MVIC) that were performed at two days before maximal eccentric exercise of the elbow flexors consisting of five sets of six maximal eccentric contractions (MaxEC) would reduce increases in biceps brachii distal myotendinous junction displacement (MTJd) over the eccentric contractions during MaxEC. Sedentary young men were randomly placed (n = 12/group) to a control group that performed two bouts of MaxEC (CONT-1st, CONT-2nd) separated by two weeks, or one of two preconditioning groups that performed 10%EC or 2MVIC at 20° elbow flexion at two days prior to MaxEC. All exercises were performed by the non-dominant arm. MTJd of each contraction was assessed by B-mode ultrasound, and its changes over sets were compared among the groups. The average MTJd from the start to the end of six eccentric contractions in the first set was similar among the groups (6.4 ± 0.7 mm). The MTJd increased from the first to fifth set, but the increase was smaller (P < .05) for the 10%EC (13 ± 6%) and 2MVIC (16 ± 9%) groups, and CONT-2nd (3 ± 6%) when compared with CONT-1st (60 ± 12%). Both 10%EC and 2MVIC groups showed smaller (P < .05) changes in all muscle damage markers after MaxEC similarly when compared with CONT-1st, but the changes were greater than those after CONT-2nd. These results supported the hypothesis that protective effect was associated with less MTJd changes, suggesting that this is associated with the mechanisms underpinning the preconditioning effect on muscle damage.

Effects of descending or ascending stair exercise on body composition, insulin sensitivity, and inflammatory markers in young Chinese women with obesity: A randomized controlled trial

We examined the effects of descending (DSE) or ascending (ASE) stair exercise on body composition, insulin sensitivity, and inflammatory markers in young Chinese women with obesity. Thirty-six participants were randomly assigned into three groups DSE, ASE and a control group. The DSE and ASE groups performed three sessions of stair walking per week for 12 weeks with a gradual increase in repetitions. Following the exercise interventions, body composition related variables obtained by Dual-energy X-ray absorptiometry scans significantly decreased. Abdominal fat decreased in the DSE group only. Moreover, Insulin sensitivity improved significantly 3.5-fold in the DSE group compared with ASE group (insulin: -33.2% vs. -9.8%, homoeostasis model assessment for insulin resistance: -35.6% vs. -10.8%). Pro-inflammatory factors showed significant decreases in tumour necrosis factor-α (TNF-α) (-39.9% vs. -23.2%) for both intervention groups. The reduction in TNF-α concentrations in the DSE group was significantly different compared to the other two groups. Interleukin-6 significantly decreased in both exercise protocols. Our results show that 12-weeks induced stair walking improved body composition parameters in Chinese females with obesity. The results also demonstrate the superiority of the DSE protocol for improving insulin sensitivity. These findings may be attributable to the decreases observed in TNF- α levels.

Impact of Acute Eccentric versus Concentric Running on Exercise-Induced Fat Oxidation and Postexercise Physical Activity in Untrained Men

Introduction

This study aimed at comparing the rate of exercise-induced fat oxidation and postexercise free-living physical activity after constant-load flat running (FR) and downhill running (DHR) bouts at an intensity that elicited maximal fat oxidation.

Methods

Participants were 11 healthy untrained men (mean age 25.6 ± 3.3 years; VO_2max39.11 ± 8.05 ml/kg/min). The study included four visits. The first two visits determined the intensity of maximal fat oxidation during incremental FR and DHR tests. The second two visits involved constant-load FR or DHR at the intensity that elicited maximal fat oxidation in a counterbalanced order separated by two weeks. Gas exchange analysis was used to measure substrate oxidation during all exercise sessions. Sedentary time and physical activity were measured using ActiGraph triaxial accelerometers for three days including the day of exercise tests (the second day).

Results

During the incremental exercise tests, fat oxidation was significantly greater during the first stage of FR (P < 0.05) but started to increase during the fourth stage of DHR, although this did not reach significance. Of the 11 participants, 7 had greater fat oxidation during DHR. During continuous constant-load running, fat oxidation was higher during DHR than FR but at only two stages was either significant or borderline significant, and the time/group interaction was not significant. There was no significant effect on sedentary time of time/group interaction (P = 0.769), but there was a significant effect of time (P = 0.005), and there was no significant effect on total physical activity of time/group interaction (P = 0.283) or time (P = 0.602).

Conclusion

Acute aerobic eccentric exercise at an intensity eliciting maximal fat oxidation enhanced exercise-induced fat oxidation without worsening postexercise free-living physical activity, indicating it could be a useful training modality in weight management programs.

Quadriceps muscle electromyography activity during physical activities and resistance exercise modes in younger and older adults

BACKGROUND

Understanding the root cause of the age-related impairment in muscle adaptive remodelling with resistance exercise training (RET) and developing pragmatic and accessible resistance exercise for older adults, are essential research directives.

METHODS

We sought to determine whether indices of quadriceps muscle EMG activity in response to different modes of RET and activities of daily living (ADL), differed between 15 healthy younger (25 ± 3 years) and 15 older (70 ± 5 years) adults. On four separate days, participants completed a maximal voluntary contraction (MVC) of the knee extensors, followed by a 15 m walking task, stair climbing task (i.e. ADL) and lower-limb RET through body-weight squats (BW-RET) and seated knee extensions on a machine (MN-RET) or via elastic bands (EB-RET). Surface quadriceps electromyography (EMG) was measured throughout all tasks to provide indirect estimates of changes in muscle activity.

RESULTS

MVC was significantly greater in young vs. older adults (Young: 256 ± 72 vs. Old: 137 ± 48 N·m, P < 0.001). EMG activity during all exercise tasks was significantly higher in older vs. younger adults when expressed relative to maximal EMG achieved during MVC (P < 0.01, for all). In addition, relative quadriceps muscle EMG activity was significantly greater in EB-RET (Young: 20.3 ± 8.7 vs. Old: 37.0 ± 10.7%) and MN-RET (Young: 22.9 ± 10.3, vs. Old: 37.8 ± 10.8%) compared with BW-RET (Young: 8.6 ± 2.9 vs. Old: 27.0 ± 9.3%), in young and older adults (P < 0.001). However, there was no significant difference in quadriceps EMG between EB-RET and MN-RET (P > 0.05).

CONCLUSIONS

In conclusion, relative quadriceps muscle EMG activity was higher across a range of activities/exercise modes in older vs. younger adults. The similar quadriceps muscle EMG activity between EB-RET and MN-RET provides a platform for detailed investigation of the neuromuscular and muscle metabolic responses to such pragmatic forms of RET to strengthen the evidence-base for this mode of RET as a potential countermeasure to sarcopenia.

Comparison between eccentric and concentric resistance exercise training without equipment for changes in muscle strength and functional fitness of older adults

PURPOSE

The present study tested the hypothesis that resistance exercise training focusing on eccentric muscle contractions would improve muscle strength and functional physical fitness more than concentric contraction-focused resistance training in older adults.

METHODS

Healthy older adults (65-84 years) were placed into eccentric (ECC; n = 9) or concentric training group (CON; n = 8). They performed 4-6 basic manual resistance exercises focusing on either eccentric or concentric muscle contractions once at a community centre and at least twice at home a week for 8 weeks. Muscle thickness of the quadriceps femoris (MT), knee extensor maximal voluntary isometric contraction strength (MVC), 30-second chair stand (CS), 3-metre timed up and go (TUG), 2-minute step (2MS), sit and reach (SR), and static balance with eyes open and closed (Bal-EC) were assessed before and 7 days after the last community centre session.

RESULTS

Changes in MT (ECC: 21.6 ± 9.2% vs CON: 6.7 ± 7.1%), MVC (38.3 ± 22.6% vs 8.2 ± 8.4%), CS (51.0 ± 21.7% vs 34.6 ± 28.3%), TUG (16.7 ± 9.9% vs 6.3 ± 7.7%), 2MS (9.9 ± 6.0% vs 6.0 ± 7.3%) and Bal-EC (35.1 ± 6.7% vs 8.8 ± 16.2%) from baseline were greater (P < 0.05) for the ECC than the CON group.

CONCLUSION

These results show that the eccentric manual resistance exercise training was more effective for improving lower limb strength, mobility, and postural stability of older adults when compared with the concentric training. This suggests the significance of emphasising eccentric muscle contractions in movements to maintain and improve physical function.

Impact of Eccentric or Concentric Training on Body Composition and Energy Expenditure

PURPOSE

To compare the effects of 8-wk eccentric (ECC) versus concentric (CON) training using downhill and uphill running in rats on whole body composition, bone mineral density (BMD), and energy expenditure.

METHODS

Animals were randomly assigned to one of the following groups: 1) control (CTRL), 2) +15% uphill-running slope (CON), 3) -15% downhill-running slope (ECC15), and 4) -30% downhill-running slope (ECC30). Those programs enabled to achieve conditions of isopower output for CON and ECC15 and of iso-oxygen uptake (V˙O2) for CON and ECC30. Trained rats ran 45 min at 15 m·min five times per week. Total body mass, fat body mass, and lean body mass (LBM) measured through EchoMRI™, and 24-h energy expenditure including basal metabolic rate (BMR) assessed using PhenoMaster/LabMaster™ cage system were obtained before and after training. At sacrifice, the right femur was collected for bone parameters analysis.

RESULTS

Although total body mass increased in all groups over the 8-wk period, almost no change occurred for fat body mass in exercised groups (CON, -4.8 ± 6.18 g; ECC15, 0.6 ± 3.32 g; ECC30, 2.6 ± 6.01 g). The gain in LBM was mainly seen for ECC15 (88.9 ± 6.85 g) and ECC30 (101.6 ± 11.07 g). ECC was also seen to positively affect BMD. An increase in BMR from baseline was seen in exercise groups (CON, 13.9 ± 4.13 kJ·d; ECC15, 11.6 ± 5.10 kJ·d; ECC30, 18.3 ± 4.33 kJ·d) but not in CTRL one. This difference disappeared when BMR was normalized for LBM.

CONCLUSIONS

Results indicate that for iso-V˙O2 training, the impact on LBM and BMD is enhanced with ECC as compared with CON, and that for isopower but lower V˙O2 ECC, an important stimulus for adaptation is still observed. This provides further insights for the use of ECC in populations with cardiorespiratory exercise limitations.

Damage protective effects conferred by low-intensity eccentric contractions on arm, leg and trunk muscles

PURPOSE

Low-intensity eccentric contractions with a load corresponding to 10% of maximal voluntary isometric contraction strength (10% EC) attenuate muscle damage in a subsequent bout of higher-intensity eccentric contractions performed within 2 weeks for the elbow flexors, knee flexors and knee extensors. However, it is not known whether this strategy could be applied to other muscles. This study investigated whether 10% EC would confer damage protective effect on high-intensity eccentric contractions (80% EC) for nine different muscle groups.

METHODS

Untrained young men were placed to an experimental or a control group (n = 12/group). Experimental group performed 50 eccentric contractions with a load corresponding to 10% EC at 2 days prior to 50 eccentric contractions with 80% EC for the elbow flexors and extensors, pectoralis, knee flexors and extensors, plantar flexors, latissimus, abdominis and erector spinae. Control group performed 80% EC without 10% EC. Changes in maximal voluntary isometric contraction strength (MVC) and muscle soreness, plasma creatine kinase (CK) activity and myoglobin concentration after 80% EC were compared between groups by a mixed-factor ANOVA.

RESULTS

MVC recovered faster (e.g., 6-31% greater MVC at 5 days post-exercise), and peak muscle soreness was 36-54% lower for Experimental than Control group for the nine muscles (P < 0.05). Increases in plasma CK activity and myoglobin concentration were smaller for Experimental (e.g., peak CK: 2763 ± 3459 IU/L) than Control group (120,360 ± 50,158 IU/L).

CONCLUSIONS

These results showed that 10% EC was effective for attenuating the magnitude of muscle damage after 80% EC for all muscles, although the magnitude of the protective effect differed among the muscles.

Physical Activity Recommendations for Health and Beyond in Currently Inactive Populations

Widespread persistent inactivity makes continued efforts in physical activity promotion a persistent challenge. The precise content of physical activity recommendations is not broadly known, and there are concerns that the general messaging of the guidelines, including the recommendations to perform at least 150 min of at least moderate intensity physical activity per week might seem unattainable for and even actually discourage currently inactive people. Here we show that there are a myriad of ways of being physically active, and provide (in part) out-of-the-box examples of evidence based, pragmatic, easily accessible physical activity regimes below 150 min and/or with lower than moderate intensity that yield meaningful health benefits for currently inactive people.

Eccentric cycling emphasising a low cardiopulmonary demand increases leg strength equivalent to workload matched concentric cycling in middle age sedentary males

OBJECTIVES

This study determined if eccentric endurance cycling, eliciting a low cardiovascular demand, could stimulate muscle strength adaptations in sedentary middle-aged males.

DESIGN

Twenty-four middle-aged sedentary males were allocated to concentric (CON) or matched workload eccentric (ECC) cycling (60% peak concentric workload) according to their maximal voluntary isometric quadriceps strength.

METHODS

Seventeen participants [42.7±8.3 years, BMI 28.6±5.2, peak oxygen consumption [30.5±5.8mLkg^-1min^-1] completed 8 weeks (2 sessions per week) of CON (n=8) or ECC (n=9) cycle training. Incline leg press (6RM), maximal voluntary isometric contraction (MVIC) torque of the quadriceps and peak oxygen consumption were measured at baseline and 8 weeks.

RESULTS

Eccentric cycle training resulted in low cardiovascular demand (CON 154±2; ECC 95±3bmin^-1P<0.05) and ratings of perceived exertion (CON 14.9±0.3; ECC 9.5±0.3/20 P<0.05). Peak oxygen consumption improved within the CON group (Baseline 27.4±2.1; 8 weeks: 30.0±1.7mLkg^-1min^-1P<0.05) and not within the ECC group (Baseline 33.2±1.5; 8 weeks 33.3±1.6mLkg^-1min^-1) following training. 6RM (CON 176±20; ECC 192±11kg) and MVIC (CON 199±25; ECC 199±25Nm) strength were equivalent at baseline (P>0.05). Both groups significantly increased 6RM (CON 13.0±3.0; ECC 10.7±3.2%) and MVIC (CON 12.9±4.3; ECC 18.8±3.0%) relative to their own baseline (P<0.05). Therefore, improved leg strength was equivalent between CON and ECC groups despite the varied training (P>0.05).

CONCLUSIONS

In sedentary middle age males, eccentric endurance cycling with a low cardiovascular demand, increased both quadriceps isometric and 6RM strength comparable to a matched workload concentric cycling program.