Neuromuscular adaptations to concurrent training in the elderly: effects of intrasession exercise sequence

The aim of this study was investigate the effects of different intrasession exercise orders in the neuromuscular adaptations induced by concurrent training in elderly. Twenty-six healthy elderly men (64.7?±?4.1 years), were placed into two concurrent training groups: strength prior to (SE, n?=?13) or after (ES, n?=?13) endurance training. Subjects trained strength and endurance training during 12 weeks, three times per week performing both exercise types in the same training session. Upper and lower body one maximum repetition test (1RM) and lower-body isometric peak torque (PTiso) and rate of force development were evaluated as strength parameters. Upper and lower body muscle thickness (MT) was determined by ultrasonography. Lower-body maximal surface electromyographic activity of vastus lateralis and rectus femoris muscles (maximal electromyographic (EMG) amplitude) and neuromuscular economy (normalized EMG at 50 % of pretraining PTiso) were determined. Both SE and ES groups increased the upper- and lower-body 1RM, but the lower-body 1RM increases observed in the SE was higher than ES (35.1?±?12.8 vs. 21.9?±?10.6 %, respectively; P?<?0.01). Both SE and ES showed MT increases in all muscles evaluated, with no differences between groups. In addition, there were increases in the maximal EMG and neuromuscular economy of vastus lateralis in both SE and ES, but the neuromuscular economy of rectus femoris was improved only in SE (P?<?0.001). Performing strength prior to endurance exercise during concurrent training resulted in greater lower-body strength gains as well as greater changes in the neuromuscular economy (rectus femoris) in elderly.     

The effects of aerobic exercise combined with resistance training on inflammatory factors and heart rate variability in middle‐aged and elderly women with type 2 diabetes mellitus

ObjectiveThis study investigated the effects of aerobic exercise combined with resistance training on serum inflammatory factors and heart rate variability (HRV) in women with type 2 diabetes mellitus (T2DM).MethodsA total of 30 patients with diabetic cardiovascular autonomic neuropathy (DCAN) were randomly divided into a control group (n = 15) and an exercise group (n = 15). The control group was treated with routine hypoglycemic drugs, while the exercise group was treated with routine hypoglycemic drugs + resistance training (AE + RT). The levels of fasting plasma glucose (FBG), two‐hour plasma glucose (2hPG), serum inflammatory factors C‐reactive protein (CRP), interleukin‐6 (IL‐6) and tumor necrosis factor alpha (TNF‐α) were measured before and after the intervention. The HRV was evaluated by 24‐h ambulatory electrocardiogram.ResultsAfter the intervention, the levels of FBG, 2hPG, serum inflammatory factors, IL‐6 and TNF‐α in the exercise group were significantly lower than those in the control group (p < .05) with no significant differences in serum CRP (p > .05). After the intervention, the HRV time domain and frequency domain indexes in the two groups were significantly improved compared with those before the exercise experiment (p < .01) and with no significant difference in (lnlf) (p > .05). The time‐domain indexes, i.e., SDNN and RMSSD, as well as the frequency domain index, i.e., (lnhf), were significantly higher in the exercise group than in the control group, whereas lnlf/lnhf were significantly lower than those in the control group (p < .05).ConclusionsCompared with routine hypoglycemic drug therapy, combining aerobic exercise and resistance training helped to reduce the level of blood glucose and serum inflammatory factors in T2DM patients with DCAN, and improved autonomic nerve function.     

Concurrent resistance and aerobic training as protection against heart disease

Summary

This study was designed to compare the effects of aerobic and concurrent aerobic and resistance training on their ability to slow the rate of development and progression of coronary heart disease (CHD) in young adult males at low risk, as determined by the Framingham risk assessment (FRA) score. Subjects were assigned to 16 weeks of three-times weekly aerobic training (AT) (n = 13), concurrent aerobic and resistance training (CART) (n = 13) or no exercise (NO) (n = 12). Both AT and CART resulted in significant (p < 0.05) changes in total cholesterol (from 173.67 ± 29.93 to 161.75 ± 26.78 mg.dl^-1 and from 190.00 ± 38.20 to 164.31 ± 28.73 mg.dl^-1, respectively), smoking status (from 12.25 ± 5.08 to 10.33 ± 5.37 cigarettes per day and 12.00 ± 4.71 to 8.77 ± 5.10 cigarettes per day, respectively), high-density lipoprotein cholesterol (from 47.00 ± 11.85 to 57.50 ± 5.99 mg.dl^-1 and 34.00 ± 8.53 to 46.77 ± 14.32 mg.dl^-1, respectively), systolic blood pressure (from 126.17 ± 7.00 to 122.33 ± 3.17 mmHg and 131.54 ± 9.28 to 121.69 ± 7.87 mmHg, respectively) and therefore FRA score (from 3.58 ± 2.19 to 1.33 ± 2.27 and 5.77 ± 3.09 to 2.46 ± 2.90, respectively). Both modes of exercise were found to be equally effective in reducing CHD risk. These findings support the inclusion of resistance training into an aerobic training programme to lower CHD risk, which will afford subjects the unique benefits of each mode of exercise.     

Effects of single vs. multiple-set short-term strength training in elderly women

The strength training has been shown to be effective for attenuating the age-related physiological decline. However, the adequate volume of strength training volume adequate to promote improvements, mainly during the initial period of training, still remains controversial. Thus, the purpose of this study was to compare the effects of a short-term strength training program with single or multiple sets in elderly women. Maximal dynamic (1-RM) and isometric strength, muscle activation, muscle thickness (MT), and muscle quality (MQ = 1-RM and MT quadriceps quotient) of the knee extensors were assessed. Subjects were randomly assigned into one of two groups: single set (SS; n = 14) that performed one set per exercise or multiple sets (MS; n = 13) that performed three-sets per exercise, twice weekly for 6 weeks. Following training, there were significant increases (p ≤ 0.05) in knee extension 1-RM (16.1 ± 12 % for SS group and 21.7 ± 7.7 % for MS group), in all MT (p ≤ 0.05; vastus lateralis, rectus femoris, vastus medialis, and vastus intermedius), and in MQ (p ≤ 0.05); 15.0 ± 12.2 % for SS group and 12.6 ± 7.2 % for MS group), with no differences between groups. These results suggest that during the initial stages of strength training, single- and multiple-set training demonstrate similar capacity for increasing dynamic strength, MT, and MQ of the knee extensors in elderly women.     

Effect of Exercise and Meals on Continuous Glucose Monitor Data in Healthy Individuals Without Diabetes

Objective:The aim of these analyses was to characterize the effect of exercise and meals on glucose concentrations in healthy individuals without diabetes.Methods:Healthy individuals without diabetes (age ≥6 years) with nonobese body mass index were enrolled at 12 centers within the T1D Exchange Clinic Network. Participants wore a blinded Dexcom G6 for up to ten days. Throughout this sensor wear, participants completed a daily log indicating times and type of any exercise and start times of meals and snacks.Results:A total of 153 participants (age 7-80 years) were included in the analyses. Exercise induced a mean change of −15 ± 18 mg/dL from baseline to nadir sensor glucose level. Mean nadir glucose concentration during nights following exercise days was 82 ± 11 mg/dL compared with 85 ± 11 mg/dL during nights following nonexercise days (P = .05). Mean change from baseline to nadir sensor glucose level during aerobic exercise was −15 ± 18 and −9 ± 12 mg/dL for resistance exercise (P = .25). Overnight nadir glucose during nights following aerobic and resistance exercise was 83 ± 12 and 76 ± 14 mg/dL, respectively (P = .25). Overall mean peak postprandial glucose per participant increased from 93 ± 10 mg/dL premeal to 130 ± 13 mg/dL with an average time to peak glucose per participant of 97 ± 31 minutes. Consumption of alcohol on the day prior did not impact overnight mean or nadir glucose.Conclusion:The present analysis provides important data characterizing the effect of exercise and meals on glucose in healthy individuals without diabetes. These data provide a repository to which future therapies, whether pharmacologic or technologic, can be compared.     

Rehabilitation effects of land and water-based aerobic exercise on lung function,dyspnea, and exercise capacity in patients with chronic obstructive pulmonary disease: A systematic review and meta-analysis

Background:We sought to synthesize the evidence about aerobic exercise intervention during pulmonary rehabilitation, and to further explore the difference in rehabilitation effects between water and land-based aerobic exercise. This review''s purpose is to provide a basis by which practitioners and therapists can select and create appropriate therapeutic programs.Methods:Data of randomized and quasi-randomized controlled trials comparing training group (TG, aerobic exercise in water or land) and control group (CG, usual care) in chronic obstructive pulmonary disease (COPD) patients (January 1, 2000–December 28, 2019) were obtained from the Cochrane Library, PubMed, Embase, China National Knowledge Infrastructure, and Wanfang databases. Two researchers independently reviewed the literature, extracted the data, and evaluated the quality of the literature. Review Manager software (Rev Man 5.3; Cochrane, London, UK) was used for meta-analysis. The rehabilitation effect of water- or land based aerobic exercise was evaluated by subgroup analysis. The proposed systematic review details were registered in PROSPERO (CRD 42020168331).Results:Eighteen studies (1311 cases of COPD) were included. Meta-analysis results show that compared with the control group, the dyspnea level and functional and endurance exercise capacity in COPD patients were significantly improved after aerobic exercise (P < .05), but there was no significant change in lung function (P > .05). Compared with land-based aerobic exercise, water-based aerobic exercise significantly improved the endurance exercise capacity in COPD patients (mean difference [MD]: 270.18, 95% CI: 74.61–465.75).Conclusion:Medium to high-quality evidence shows that aerobic exercise can effectively improve dyspnea and exercise capacity in COPD patients. Compared with land-based aerobic exercise, water-based aerobic exercise had a significant additional effect in improving the endurance exercise capacity of COPD patients.     

Satellite cells in human skeletal muscle; from birth to old age

Changes in satellite cell content play a key role in regulating skeletal muscle growth and atrophy. Yet, there is little information on changes in satellite cell content from birth to old age in humans. The present study defines muscle fiber type-specific satellite cell content in human skeletal muscle tissue over the entire lifespan. Muscle biopsies were collected in 165 subjects, from different muscles of children undergoing surgery (<18 years; n = 13) and from the vastus lateralis muscle of young adult (18–49 years; n = 50), older (50–69 years; n = 53), and senescent subjects (70–86 years; n = 49). In a subgroup of 51 aged subjects (71 ± 6 years), additional biopsies were collected after 12 weeks of supervised resistance-type exercise training. Immunohistochemistry was applied to assess skeletal muscle fiber type-specific composition, size, and satellite cell content. From birth to adulthood, muscle fiber size increased tremendously with no major changes in muscle fiber satellite cell content, and no differences between type I and II muscle fibers. In contrast to type I muscle fibers, type II muscle fiber size was substantially smaller with increasing age in adults (r = −0.56; P < 0.001). This was accompanied by an age-related reduction in type II muscle fiber satellite cell content (r = −0.57; P < 0.001). Twelve weeks of resistance-type exercise training significantly increased type II muscle fiber size and satellite cell content. We conclude that type II muscle fiber atrophy with aging is accompanied by a specific decline in type II muscle fiber satellite cell content. Resistance-type exercise training represents an effective strategy to increase satellite cell content and reverse type II muscle fiber atrophy.

Electronic supplementary material

The online version of this article (doi:10.1007/s11357-013-9583-2) contains supplementary material, which is available to authorized users.     

Short-term strength training improves muscle quality and functional capacity of elderly women

To assess effects of a short-term strength training (ST) program on muscle quality (MQ) and functional capacity, 36 sedentary elderly women (age = 66.0 ± 8 year, height = 159.1 ± 9.2 cm, body mass = 68.3 ± 12.1 kg, body fat = 37.0 ± 4.2 %) were randomly divided into an experimental group (EG; n = 19) or a control group (CG; n = 17). The EG performed two to three sets of 12–15 repeats of leg press, knee extension, and knee flexion exercises, 2 days/week for 6 weeks. Before and after training, lower body one repetition maximum (1RM), functional performance tests, quadriceps femoris muscle thickness (MT), and muscle quality (MQ) (1RM and quadriceps MT quotient) were assessed. After training, only the EG showed significant improvements in 1RM (p < 0.05), 30-s sit-to-stand (p < 0.001), and 8 foot up-and-go (p < 0.001). In addition, only in the EG, significant increases in all quadriceps femoris MT measurements (vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris) (p ≤ 0.05), and MQ (p < 0.001) were demonstrated. No changes were observed in the CG. Furthermore, there were significant associations between individual changes in MQ and corresponding changes in 30-s sit-to-stand (r = 0.62, p < 0.001), and 8 foot up-and-go (r = −0.71, p < 0.001). In conclusion, a ST program of only 6 weeks was sufficient to enhance MQ of the knee extensors in elderly women, which resulted in beneficial changes in functional capacity.     

The influence of physical exercise and leisure activity on neuropsychological functioning in older adults

It has been suggested that leisure activity and physical exercise can be a protective factor for neuropsychological functions and are associated with a reduced risk of dementia. Thus, the purpose of this study was to investigate the influence of physical exercise and leisure on the neuropsychological functions of healthy older adults. The sample was composed of 51 sedentary female volunteers who were 60–70 years old and were distributed into three groups: A—control, B—leisure, and C—training. Volunteers were submitted to a physical and neuropsychological assessment at baseline and after 6 months. Groups A and B were monitored longitudinally three times a week. Group C improved their neuropsychological functioning and oxygen consumption compared to groups A and B (p = <0.05). The neuropsychological functions of groups A and B were significantly worse after 6 months of monitoring (p = <0.05). The data suggest that physical exercise improves neuropsychological functioning, although leisure activities may also improve this functioning. Thus, an aerobic physical fitness program can partially serve as a non-medication alternative for maintaining and improving these functions in older adults; however, leisure activities should also be considered.     

Effects of eccentric-focused and conventional resistance training on strength and functional capacity of older adults

The aim of the study was to assess the effect of eccentric training using a constant load with longer exposure time at the eccentric phase on knee extensor muscle strength and functional capacity of elderly subjects in comparison with a conventional resistance training program. Twenty-six healthy elderly women (age = 67 ± 6 years) were randomly assigned to an eccentric-focused training group (ETG; n = 13) or a conventional training group (CTG; n = 13). Subjects underwent 12 weeks of resistance training twice a week. For the ETG, concentric and eccentric phases were performed using 1.5 and 4.5 s, respectively, while for CTG, each phase lasted 1.5 s. Maximum dynamic strength was assessed by the one-repetition maximum (1RM) test in the leg press and knee extension exercises, and for functional capacity, subjects performed specific tests (6-m walk test, timed up-and-go test, stair-climbing test, and chair-rising test). Both groups improved knee extension 1RM (24–26 %; p = 0.021), timed up-and-go test (11–16 %; p < 0.001), 6-m walk test (9–12 %; p = 0.004), stair-climbing test (8–13 %; p = 0.007), and chair-rising test (15–16 %; p < 0.001), but there was no significant difference between groups. In conclusion, the strategy of increasing the exposure time at the eccentric phase of movement using the same training volume and intensity does not promote different adaptations in strength or functional capacity compared to conventional resistance training in elderly woman.     

Distinguishing exercise intolerance in early‐stage pulmonary hypertension with invasive exercise hemodynamics: Rest V E/VCO2 and ETCO2 identify pulmonary vascular disease

BackgroundAmong subjects with exercise intolerance and suspected early‐stage pulmonary hypertension (PH), early identification of pulmonary vascular disease (PVD) with noninvasive methods is essential for prompt PH management.HypothesisRest gas exchange parameters (minute ventilation to carbon dioxide production ratio: V _E/VCO₂ and end‐tidal carbon dioxide: ETCO₂) can identify PVD in early‐stage PH.MethodsWe conducted a retrospective review of 55 subjects with early‐stage PH (per echocardiogram), undergoing invasive exercise hemodynamics with cardiopulmonary exercise test to distinguish exercise intolerance mechanisms. Based on the rest and exercise hemodynamics, three distinct phenotypes were defined: (1) PVD, (2) pulmonary venous hypertension, and (3) noncardiac dyspnea (no rest or exercise PH). For all tests, *p < .05 was considered statistically significant.ResultsThe mean age was 63.3 ± 13.4 years (53% female). In the overall cohort, higher rest V _E/VCO₂ and lower rest ETCO₂ (mm Hg) correlated with high rest and exercise pulmonary vascular resistance (PVR) (r ~ 0.5–0.6*). On receiver‐operating characteristic analysis to predict PVD (vs. non‐PVD) subjects with noninvasive metrics, area under the curve for pulmonary artery systolic pressure (echocardiogram) = 0.53, rest V _E/VCO₂ = 0.70* and ETCO₂ = 0.73*. Based on this, optimal thresholds of rest V _E/VCO₂ > 40 mm Hg and rest ETCO₂ < 30 mm Hg were applied to the overall cohort. Subjects with both abnormal gas exchange parameters (n = 12, vs. both normal parameters, n = 19) had an exercise PVR 5.2 ± 2.6* (vs. 1.9 ± 1.2), mPAP/CO slope with exercise 10.2 ± 6.0* (vs. 2.9 ± 2.0), and none included subjects from the noncardiac dyspnea group.ConclusionsIn a broad cohort of subjects with suspected early‐stage PH, referred for invasive exercise testing to distinguish mechanisms of exercise intolerance, rest gas exchange parameters (V _E/VCO₂ > 40 mm Hg and ETCO₂ < 30 mm Hg) identify PVD.     

Exercise-training-induced changes in metabolic capacity with age: the role of central cardiovascular plasticity

Although aging is typically associated with a decline in maximal oxygen consumption (VO_2max), young and old subjects, of similar initial muscle metabolic capacity, increased quadriceps VO_2max equally when this small muscle mass was trained in isolation. As it is unclear if this preserved exercise-induced plasticity with age is still evident with centrally challenging whole body exercise, we assessed maximal exercise responses in 13 young (24 ± 2 years) and 13 old (60 ± 3 years) males, matched for cycling VO_2max (3.82 ± 0.66 and 3.69 ± 0.30 L min⁻¹, respectively), both before and after 8 weeks of high aerobic intensity cycle exercise training. As a consequence of the training both young and old significantly improved VO_2max (13 ± 6 vs. 6 ± 7 %) and maximal power output (20 ± 6 vs. 10 ± 6 %, respectively) from baseline, however, the young exhibited a significantly larger increase than the old. Similarly, independently assessed maximal cardiac output (Q_max) tended to increase more in the young (16 ± 14 %) than in the old (11 ± 12 %), with no change in a-vO₂ difference in either group. Further examination of the components of Q_max provided additional evidence of reduced exercise-induced plasticity in both maximal heart rate (young −3 %, old 0 %) and stroke volume (young 19 ± 15, old 11 ± 11 %) in the old. In combination, these findings imply that limited central cardiovascular plasticity may be responsible, at least in part, for the attenuated response to whole body exercise training with increasing age.     

Strength training-induced responses in older adults: attenuation of descending neural drive with age

Although reductions in resting H-reflex responses and maximal firing frequency suggest that reduced efferent drive may limit muscle strength in elderly, there are currently no reports of V-wave measurements in elderly, reflecting the magnitude of efferent output to the muscle during maximal contraction. Furthermore, it is uncertain whether potential age-related neural deficiencies can be restored by resistance training. We assessed evoked reflex recordings in the triceps surae muscles during rest and maximal voluntary contraction (MVC), rate of force development (RFD), and muscle mass in seven elderly (74 ± 6 years) males before and after 8 weeks of heavy resistance training, contrasted by seven young (24 ± 4 years) male controls. At baseline, m. soleus (SOL) V/M ratio (0.124 ± 0.082 vs. 0.465 ± 0.197, p < 0.05) and H/M ratio (0.379 ± 0.044 vs. 0.486 ± 0.101 p = 0.07) were attenuated in elderly compared to young. Also, SOL H-reflex latency (33.29 ± 2.41 vs. 30.29 ± 0.67 ms, p < 0.05) was longer in elderly. The reduced neural drive was, despite similar leg muscle mass (10.7 ± 1.2 vs. 11.5 ± 1.4 kg), mirrored by lower MVC (158 ± 48 vs. 240 ± 54 Nm, p < 0.05) and RFD (294 ± 126 vs. 533 ± 123 Nm s⁻¹, p < 0.05) in elderly. In response to training SOL V/M ratio (0.184 ± 0.092, p < 0.05) increased in the elderly, yet only to a level ∼40 % of the young. This was accompanied by increased MVC (190 ± 70 Nm, p < 0.05) and RFD (401 ± 147 Nm⋅s⁻¹, p < 0.05) to levels of ∼80 % and ∼75 % of the young. H/M ratio remained unchanged. These findings suggest that changes in supraspinal activation play a significant role in the age-related changes in muscle strength. Furthermore, this motor system impairment can to some extent be improved by heavy resistance training.     

Atrial structure and function in middle‐aged,physically‐active males and females: A cardiac magnetic resonance study

Recent studies have reported on an association between endurance sport, atrial enlargement and the development of lone atrial fibrillation in younger, male cohorts. The atrial morphology and function of middle‐aged, physically‐active males and females have not been well studied. We hypothesized that middle‐aged males would demonstrate larger left atrium (LA) and right atrium (RA) volumes compared to females, but atrial function would not differ. LA and RA volume and function were evaluated at rest in healthy adults, using a standardized 3.0Tesla cardiac magnetic resonance protocol. Physical activity, medical history, and maximal oxygen consumption (V˙O2peak) were also assessed. Physically‐active, middle‐aged men (n = 60; 54 ± 5 years old) and women (n = 30; 54 ± 5 years old) completed this study. Males had a higher body mass index, systolic blood pressure, and V˙O2peak than females (p < .05 for all), despite similar reported physical activity levels. Absolute and BSA and height‐indexed LA and RA maximum volumes were higher in males relative to females, despite no differences in ejection fractions (p < .05 for all). In multivariable regression, male sex p < .001) and V˙O2peak (p = .004) were predictors of LA volume (model R ² = 0.252), whereas V˙O2peak (p < .001), male sex (p = .03), and RV EF (p < .05) were predictors of RA volume (model R ² = 0.377). While middle‐aged males exhibited larger atrial volumes relative to females, larger, prospective studies are needed to explore the magnitude of physiologic atrial remodeling and functional adaptations in relation to phenotypic factors.     

Impact of low-volume,high-intensity interval training on maximal aerobic capacity,health-related quality of life and motivation to exercise in ageing men

There is a demand for effective training methods that encourage exercise adherence during advancing age, particularly in sedentary populations. This study examined the effects of high-intensity interval training (HIIT) exercise on health-related quality of life (HRQL), aerobic fitness and motivation to exercise in ageing men. Participants consisted of males who were either lifelong sedentary (SED; N = 25; age 63 ± 5 years) or lifelong exercisers (LEX; N = 19; aged 61 ± 5 years). V˙O2max and HRQL were measured at three phases: baseline (Phase A), week seven (Phase B) and week 13 (Phase C). Motivation to exercise was measured at baseline and week 13. V˙O2max was significantly higher in LEX (39.2 ± 5.6 ml kg min⁻¹) compared to SED (27.2 ± 5.2 ml kg min⁻¹) and increased in both groups from Phase A to C (SED 4.6 ± 3.2 ml kg min⁻¹, 95 % CI 3.1 – 6.0; LEX 4.9 ± 3.4 ml kg min⁻¹, 95 % CI 3.1–6.6) Physical functioning (97 ± 4 LEX; 93 ± 7 SED) and general health (70 ± 11 LEX; 78 ± 11 SED) were significantly higher in LEX but increased only in the SED group from Phase A to C (physical functioning 17 ± 18, 95 % CI 9–26, general health 14 ± 14, 95 % CI 8–21). Exercise motives related to social recognition (2.4 ± 1.2 LEX; 1.5 ± 1.0 SED), affiliation (2.7 ± 1.0 LEX; 1.6 ± 1.2 SED) and competition (3.3 ± 1.3 LEX; 2.2 ± 1.1) were significantly higher in LEX yet weight management motives were significantly higher in SED (2.9 ± 1.1 LEX; 4.3 ± 0.5 SED). The study provides preliminary evidence that low-volume HIIT increases perceptions of HRQL, exercise motives and aerobic capacity in older adults, to varying degrees, in both SED and LEX groups.     

Influence of exercise intensity on training-induced tendon mechanical properties changes in older individuals

This study compared the effects of low vs. high intensity training on tendon properties in an elderly population. Participants were pair-matched (gender, habitual physical activity, anthropometrics, and baseline knee extension strength) and then randomly assigned to low (LowR, i.e., ~40 % 1RM) or high (High R, i.e., ~80 % 1RM) intensity resistance training programmes for 12 weeks, 3× per week (LowR, n = 9, age 74 ± 5 years; HighR, n = 8, age 68 ± 6 years). Patellar tendon properties (stiffness [K], Young’s modulus [YM], cross-sectional area [T_CSA], and tendon length [T_L]) were measured pre and post training using a combination of magnetic resonance imaging (MRI), B-mode ultrasonography, dynamometry, electromyography and ramped isometric knee extensions. With training K showed no significant change in the LowR group while it incremented by 57.7 % in the HighR group (p < 0.05). The 51.1 % group difference was significant (p < 0.05). These differences were still apparent when the data was normalized for T_CSA and T_L, i.e., significant increase in YM post-intervention in HighR (p < 0.05), but no change in LowR. These findings suggest that when prescribing exercise for a mixed genders elderly population, exercise intensities of ≤40 % 1RM may not be sufficient to affect tendon properties.     

Comparison of aerobic and combined aerobic and resistance training on low-density lipoprotein cholesterol concentrations in men

Summary

While aerobic training and, to a lesser degree, resistance training are known to reduce blood concentrations of low-density lipoprotein cholesterol (LDL-C), little is known about the effects of a combination of aerobic and resistance training on LDL-C concentrations. The aim of the investigation was to examine the effects of 16 weeks of no exercise, aerobic training or a combination of aerobic and resistance training on lowering blood concentrations of LDL-C.Thirty-eight healthy, previously untrained men (mean age: 25 years and six months) with borderline high blood LDL-C concentrations volunteered to participate in this investigation. Each subject’s blood LDL-C concentrations were measured following a nine- to 12-hour fasting period and prior to any exercise. Aerobic training consisted of exercise using a combination of treadmills, rowers, steppers and cycle ergometers. Combined aerobic and resistance training consisted of a combination of aerobic training at 60% of heart rate maximum, and resistance training using eight prescribed exercises performed for two sets of 15 repetitions at 60% of the estimated one-repetition maximum (1-RM).The no-exercise group was found to have had no significant (p ≤ 0.05) change in blood LDL-C concentrations (from 4.12 ± 0.27 to 4.21 ± 0.42 mmol.l^-1), whereas the aerobic training and combined training groups showed significant and similar (p = 0.123) decreases in blood LDL-C concentrations (from 3.64 ± 2.87 to 2.87 ± 0.64 mmol.l^-1 and from 4.39 ± 1.04 to 3.23 ± 0.71 mmol.l^-1, respectively). This investigation indicates that a larger dose of aerobic exercise does not necessarily equate to a greater improvement in LDL-C concentrations if the lost aerobic exercise time is replaced with resistance exercise.     

Effect of resistance training with different frequencies and detraining on muscular strength and oxidative stress biomarkers in older women

The aim of this study was to compare the effect of resistance training (RT) performed with different frequencies followed by a detraining period on muscular strength and oxidative stress (OS) biomarkers in older women. Twenty-seven physically independent women (68.8 ± 4.8 years, 69.1 ± 14.3 kg, 156.0 ± 6.5 cm, and 28.3 ± 4.9 to kg.m⁻²) were randomly assigned to perform a RT program for 2 or 3 days per week (G2X = 13 vs. G3X = 14) for 12 weeks followed by 12 weeks of detraining period. One repetition maximum (1RM) tests were used as measures of muscular strength (three exercises, three attempts for each exercise, 3–5 min of rest between attempts, and 5 min of rest between exercises). Advanced oxidized protein products (AOPP) and total radical-trapping antioxidant parameter (TRAP) were used as oxidative stress indicators. Both groups increased muscular strength after 12 weeks of training (P < 0.05) in chest press (G2X = +11.9 % vs. G3X = +27.5 %, P < 0.05), knee extension (G2X = +18.4 % vs. G3X = +16.7 %, P > 0.05), and preacher curl (G2X = +37.6 % vs. G3X = +36.7 %, P > 0.05). On the other hand, 12 weeks of detraining were not sufficient to eliminate the major effects produced by RT on muscular strength, although a significant decrease (P < 0.05) has been observed for chest press (G3X = −9.1 % vs. G2X = −10.2 %, P > 0.05), knee extension (G2X = −14.9 % vs. G3X = −12.1 %, P > 0.05), and preacher curl (G2X = −20.5 % vs. G3X = −17.4 %, P > 0.05). Pre- to post-training, both groups showed significant (P < 0.05) increases in TRAP (G2X = +6.9 % vs. G3X = +15.1 %) with no statistical significant difference between the groups (P > 0.05), and the scores remained elevated compared to pre-training after 12 weeks of detraining. AOPP was not changed by RT or detraining (P > 0.05). The results suggest that a 12-week RT program with a frequency of 2 days per week may be sufficient to improve muscular strength and OS in older women and detraining for 12 weeks does not completely reverse the changes induced by RT.     

Relationship between quadriceps femoris echo intensity,muscle power,and functional capacity of older men

Increased proportion of non-contractile elements can be observed during aging by enhanced skeletal muscle echo intensity (EI). Studies have demonstrated that an increase in rectus femoris EI may affect physical performance. However, it is still unknown whether the whole quadriceps femoris EI (QEI) influences strength, power, and functional capacity of an older population. Therefore, the aim of the present study was to determine the correlation between QEI, the four individual quadriceps portions EI, and muscular performance of older men. Fifty sedentary healthy men (66.1 ± 4.5 years, 1.75 ± 0.06 m, 80.2 ± 11.0 kg) volunteered for the present study. The QEI and EI of the four quadriceps portions were calculated by ultrasound imaging. Knee extension one repetition maximum (1RM), isometric peak torque (PT), and rate of torque development (RTD) were obtained as measures of muscular strength. Muscular power was determined by knee extension with 60 % of 1RM and countermovement jump (CMJ). The 30-s sit-to-stand test was evaluated as a functional capacity parameter. QEI and all individual EI were correlated to functional capacity and power during CMJ (p ≤ 0.05), but rectus femoris EI was not related to knee extension average power (p > 0.05). There were significant correlations between all EI variables, 1RM, PT, and RTD at 0.2 s (p ≤ 0.05), but only vastus medialis EI and QEI were correlated to RTD at 0.05 s (p ≤ 0.05). The results of the present study suggest that QEI is related to muscular power and functional capacity of older subjects, but the EI of some individual quadriceps portions may underestimate the correlations with muscular performance.