The efficacy of high-load resistance training in combination with aerobic training in patients with coronary artery disease: a dose-dependent randomised, controlled clinical trial

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Slovenian Research Agency

Background

The combination of resistance training (RT) and aerobic training (AT) was shown to be superior compared to AT, although most studies applied only low-loads (LL) to moderate-loads in RT. Therefore, it remains to be elucidated whether high-load (HL) RT elicits greater improvement in maximal aerobic capacity and maximal muscle strength compared to low-load (LL) RT in combination to AT in patients with coronary artery disease (CAD).

Purpose

The aim of our study was to investigate the effects of HL-RT and LL-RT combined with AT in comparison to AT on maximal aerobic capacity, muscle strength and health-related quality of life.

Methods

We randomised 79 patients with CAD to HL-RT+AT (70 %-80% of one repetition maximum [1-RM]), LL-RT+AT (35%-40% of 1-RM) or AT group and 59 patients with mean (SD) age 61 (8) years and left ventricular ejection fraction 53 (9) % completed 12 weeks (36 training sessions) of the study. After the initial ambulatory screening by cardiologist and cardiopulmonary exercise test, patients were familiarised with proper lifting and breathing technique, and performed 1-RM test on leg press machine. During the training, the RT load progressively increased from 70% of 1-RM (6–11 repetitions per set) to 80% of 1-RM (6–8 reps per set) in HL-RT group and from 35% of 1-RM (12–22 reps per set) to 40% of 1-RM (12–16 reps per set) in LL-RT group in the first seven weeks of the intervention. Following re-evaluation of 1-RM, the training load in HL-RT group was progressed from 70% 1-RM (11 reps per set) to 80% 1-RM (6–8 reps per set), and the load in LL-RT group was progressed from 35% 1-RM (22 reps per set) to 40% 1-RM (12–16 reps per set). All patients performed AT consisted of 3-5 min of work-load interval cycling separated by 2 min of unloaded cycling progressing from 50% to 80% maximal workload achieved at baseline cardiopulmonary exercise test. We measured maximal aerobic capacity (VO2 max), maximal voluntary contraction (MVC) and quality of life at baseline and post-training.

Results

Exercise training was safe and associated with improvement in VO2 max (p < 0.01) in all training groups, whereas only LL-RT and HL-RT group improved MVC (both p < 0.001). Following training, VO2 max increased more in HL-RT group compared to AT group (+18 %, p = 0.032), and MVC increased more in HL-RT group compared to LL-RT group (+7 %, p = 0.018) and AT group (+16 %, p < 0.001). HL-RT group improved mental functioning component of short form 12-item quality of life questionnaire (+6 points, p = 0.003), with no significant difference compared to other training modalities.

Conclusions

RT on top of routine CR management, is safe and efficacious training modality for patients with CAD enrolled in cardiac rehabilitation.

Sedentary behaviour and physical activity following multimodal exercise-based cardiac rehabilitation in patients with coronary artery disease

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Slovenian Research Agency

Background

Despite high levels of sedentary behaviour (SB) in patients with coronary artery disease (CAD), there is still limited evidence on the efficacy of multimodal exercise interventions combined with physical activity (PA) counselling on SB and PA in cardiac rehabilitation (CR). Such combined modalities in CR may provide additional benefits for PA and SB, although this remains to be investigated.

Purpose

The aim of our study was to investigate the effects of multimodal exercise training combined with brief PA counselling on PA and SB according to sedentary status of patients with CAD.

Methods

We randomised 79 patients with CAD to low-load (LL) resistance training (RT) + aerobic training (AT) (30%-40% of one repetition maximum [1-RM]), high load RT+AT (70%-80% of 1-RM) and AT alone. The study was completed by 57 patients, with [mean (SD)] age = 61 (8) years, height = 171.8 (8.5) cm, weight = 85.12 (15.59) kg and left ventricular ejection fraction = 53 % (45,60) [median (first, third quartile)]. During the study, each patient received an hour of PA counselling and written PA brochure. Step count, daily SB, light intensity PA (LIPA) and moderate-to-vigorous PA (MVPA) were measured at baseline and post-training using triaxial accelerometer. Following baseline measurement, we stratified patients to quartiles based on their levels of SB: most sedentary, sedentary, less sedentary, least sedentary.

Results

Upon enrolment to CR patients have surpassed daily PA recommendation (+21 min, p < 0.001). All measures of PA and SB remained unchanged following training intervention (all p > 0.388). Patients classified as the most sedentary have decreased SB (-52 min/day, p = 0.001) and increased LIPA (+27 min/day, p = 0.009), while the least sedentary patients increased SB (+69 min/day, p = 0.006) and decreased LIPA (-25 min/day, p = 0.038) following the intervention. The improvement in PA was greater in the most sedentary patients (SB: +27%, p = 0.002; LIPA: +24%, p = 0.004) and in sedentary patients (SB: +24%, p = 0.009) compared to the least sedentary patients. After the training intervention, LIPA was improved more in less sedentary patients compared to the least sedentary patients (+19 %, p = 0.031). Two-way analysis of variance has demonstrated non-significant effect of time x training modality interaction on all PA and SB variables (p = 0.285-0.819).

Conclusions

The addition of RT and brief PA counselling to standard CR showed limited effects on post-training improvement in SB and MVPA. Individually tailored PA behavioural counselling based on patients’ sedentary status along with regular PA monitoring during CR should be implemented to enhance the effects of combined RT and AT in patients with CAD.

Resistance training during cardiac rehabilitation improves physical performance in patients with coronary artery disease: a randomised controlled trial

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Slovenian Research Agency

Background

Resistance training (RT) is an adjunct exercise therapy to aerobic training (AT) in cardiac rehabilitation, but it remains unknown whether the dose-dependent relationship between RT load (high load [HL] vs. low load [LL]) and improvement in anthropometry, body composition and physical performance exists in patients with coronary artery disease (CAD).

Purpose

The aim of our study was to investigate the effects of HL-RT and LL-RT on top of AT in comparison to AT on anthropometry, body composition and physical performance in patients with CAD.

Methods

A total of 79 patients with a stable CAD were randomised to HL-RT+AT (n = 21), LL-RT+AT (n = 19) or AT (n = 19) and performed 36 training sessions. Fifty-nine patients with mean (SD) age 61 (8) years and left ventricular ejection fraction 53 (9) % completed the study. AT progressed from 50 % to 80% of peak power output achieved at baseline cardiopulmonary exercise test, and RT progressed from 70% of one repetition maximum (1-RM) to 80% of 1-RM in HL-RT group, and from 35% of 1-RM to 40% of 1-RM in LL-RT group. We measured anthropometry (body mass, waist and hip circumference, and waist to hip circumference ratio), body composition (lean body mass and %, body fat mass and %, and phase angle) and physical performance evaluating upper muscle strength (arm curl and hand grip test) and lower muscle strength (five sit-to stand test, up-and-go test, heel raise test), mobility (gait speed test), flexibility (back scratch test, sit-and-reach test), balance (stork balance test) and submaximal endurance (6 min walk test distance) at baseline and post-training.

Results

Waist circumference and waist-to-hip circumference ratio decreased significantly following LL-RT (both p < 0.01), without post-training differences between training interventions in other anthropometry measures and body composition measures (all p > 0.079). HL-RT and LL-RT induced improvements in all physical performance measures, while AT alone did not improve gait speed, upper limb flexibility and performance of up-and-go test. HL-RT was associated with greater improvement in gait speed (+12 %, p =0.044), arm curl test (+13 %, p = 0.037) and time of Up-and-go test (+9 %, p <0.001) compared to AT group, while LL-RT improved more time of Up-and-Go test (+18 %, p < 0.001) and time of five sit-to-stands (+14 %, p = 0.016) compared to AT. There was no difference between HL-RT and LL-RT in post-training change of physical performance measures.

Conclusions

The addition of RT to AT is associated with greater improvements in submaximal muscle strength and mobility compared to AT and should be encouraged in future multimodal exercise-based cardiac rehabilitation.

Lifelong physical exercise delays age-associated skeletal muscle decline

Aging is usually accompanied by a significant reduction in muscle mass and force. To determine the relative contribution of inactivity and aging per se to this decay, we compared muscle function and structure in (a) male participants belonging to a group of well-trained seniors (average of 70 years) who exercised regularly in their previous 30 years and (b) age-matched healthy sedentary seniors with (c) active young men (average of 27 years). The results collected show that relative to their sedentary cohorts, muscle from senior sportsmen have: (a) greater maximal isometric force and function, (b) better preserved fiber morphology and ultrastructure of intracellular organelles involved in Ca(2+) handling and ATP production, (c) preserved muscle fibers size resulting from fiber rescue by reinnervation, and (d) lowered expression of genes related to autophagy and reactive oxygen species detoxification. All together, our results indicate that: (a) skeletal muscle of senior sportsmen is actually more similar to that of adults than to that of age-matched sedentaries and (b) signaling pathways controlling muscle mass and metabolism are differently modulated in senior sportsmen to guarantee maintenance of skeletal muscle structure, function, bioenergetic characteristics, and phenotype. Thus, regular physical activity is a good strategy to attenuate age-related general decay of muscle structure and function (ClinicalTrials.gov: NCT01679977).

Effects of whole-body cryotherapy on recovery after hamstring damaging exercise: a crossover study

The purpose of this study was to examine the effects of whole-body cryotherapy (WBC) on biochemical, pain, and performance parameters during the 5-day recovery period after damaging exercise for hamstrings. Participants completed a bout of damaging exercise for the hamstring muscles on two separate occasions (control and experimental condition) separated by 10 weeks. During the control condition, subjects received no treatment after the damaging exercise. The experimental condition consisted of WBC everyday during the recovery period. WBC included single 3-min daily exposures to low temperatures (-140 to -19 °C) in the cryo-cabin. During the recovery period, subjects were tested for biochemical markers, perceived pain sensation, and physical performance (squat jump, counter movement jump, maximal isometric torque production, and maximally explosive isometric torque production). Majority of the observed variables showed statistically significant time effects (P < 0.05) in control group, which indicates the presence of muscle damage. Significant interaction between the control and WBC condition was evident for the rate of torque development (P < 0.05). Pain measures substantially differed between the WBC and the control condition after the exercise. Results of this study are not completely supportive of the use of WBC for recovery enhancement after strenuous training.

Effects of 8 weeks of vibration training at different frequencies (1 or 15 Hz) in senior sportsmen on torque and force development and of 1 year of training on muscle fibers

OBJECTIVE

To examine the effects of 8 weeks of vibration training at different frequencies (1 and 15 Hz) on maximal isometric torque and force development in senior sportsmen, and of 1 year of heavy-resistance and vibration trainings on muscle fibers.

METHODS

Seven healthy senior sportsmen (mean age: 69.0 +/- 5.4 years) performed an 8 weeks of strength training of knee extensors. Vibrations were applied vertically to the axis of movement during training. One leg of each subject was trained at a frequency of 1 Hz, while the other leg was trained at 15 Hz. Measures of isometric peak torque (at knee-angles of 60, 90 and 120 degrees ) and force development were recorded before and after training. Four sportsmen continued a year-long heavy-resistance training adding every second week a session of vibration training. After training, muscle biopsies were harvested from their quadriceps muscles and used for structural analyses. Morphometry of muscle fibers was performed by light microscopy. Immunohistochemistry using anti-MHCemb and anti-N-CAM antibodies was performed to measure potential muscle damage. Data from muscle morphometry were compared to that of a series of vastus lateralis biopsies harvested from 12 young sportsmen and four healthy elderly.

RESULTS

Our results showed a significant increase in isometric peak torque at both 1 and 15 Hz vibration frequency in all three measured angles of the knee. There was no significant difference between the two frequencies, but we could find a higher increase in percentage of maximum power after the 1 Hz training. The results of force development showed a slight increase at the 1 Hz training in measured time frames from 0 to 50 and 200 ms, without statistical significance. A trend to significance was found at the 1 Hz training at the time window up to 200 ms. The 15 Hz training showed no significant changes of force development. Muscle biopsies show that the muscles of these well trained senior sportsmen contain muscle fibers which are 35% larger than those of sedentary elderly and, unexpectedly, 10% larger than those of young sportsmen. Despite 1 year of heavy resistance and vibration training, no evidence of muscle damage or denervation/reinnervation could be observed by light microscopy analyses, ATPase histochemistry and immunohistochemistry using anti-N-CAM or anti-MHC-emb antibodies.

DISCUSSION

Integration of vibration to conventional strength training in elderly sportsmen induces similar improvement of isometric peak torque and force development independently from the vibration frequency after 8 weeks of training, and long-term results in the surprising evidence of hypertrophic muscle fibers larger than those of young active sportsmen. The observation that the vibration training with low frequency is safe opens the possibility to test these rehabilitation procedures in sedentary elderly.