Savvas P. Tokmakidis

Hormonal Responses after Various Resistance Exercise Protocols

PURPOSE This study examined the effects of the number of sets on testosterone, cortisol, and growth hormone (hGH) responses after maximum strength (MS), muscular hypertrophy (MH), and strength endurance (SE) protocols. METHODS Eleven young men performed multi-joint dynamic exercises using MS (5 reps at 88% of one-repetition maximum (1-RM), 3-min rest) and MH (10 reps at 75% of 1-RM, 2-min rest) protocols with 2, 4, and 6 sets at each exercise; and an SE (15 reps at 60% of 1-RM, 1-min rest) with 2 and 4 sets. Hormonal concentrations were measured before exercise, immediately after, and at 15 and 30 min of recovery. RESULTS The number of sets did not affect the hormonal responses after the MS protocol. Cortisol and hGH were higher (P < 0.05) after the four-set compared with the two-set sessions in the MH and SE protocols. No differences were observed between the six-set and the four-set sessions in the MH protocol. Cortisol and hGH were higher (P < 0.05) than the MS after the SE and MH protocols, and only when four and six sets were performed in the latter. hGH was higher than the MH after the SE protocol, whether two or four sets were executed, whereas cortisol (P < 0.05) was higher after the SE protocol only when two sets were performed. Testosterone did not change with any workout. CONCLUSION The number of sets functions up to a point as a stimulus for increased hormonal concentrations in order to optimize adaptations with MH and SE protocols, and has no effect on a MS protocol. Furthermore, the number of sets may differentiate long-term adaptations with MS, MH, and SE protocols causing distinct hormonal responses.

Effects of Resistance Training on the Physical Capacities of Adolescent Soccer Players

This study examined the effects of a progressive resistance training program in addition to soccer training on the physical capacities of male adolescents. Eighteen soccer players (age: 12–15 years) were separated in a soccer (SOC; n = 9) and a strength-soccer (STR; n = 9) training group and 8 subjects of similar age constituted a control group. All players followed a soccer training program 5 times a week for the development of technical and tactical skills. In addition, the STR group followed a strength training program twice a week for 16 weeks. The program included 10 exercises, and at each exercise, 2–3 sets of 8–15 repetitions with a load 55–80% of 1 repetition maximum (1RM). Maximum strength ([1RM] leg press, bench-press), jumping ability (squat jump [SJ], countermovement jump [CMJ], repeated jumps for 30 seconds) running speed (30 m, 10 × 5-m shuttle run), flexibility (seat and reach), and soccer technique were measured at the beginning, after 8 weeks, and at the end of the training period. After 16 weeks of training, 1RM leg press, 10 × 5-m shuttle run speed, and performance in soccer technique were higher (p < 0.05) for the STR and the SOC groups than for the control group. One repetition maximum bench press and leg press, SJ and CMJ height, and 30-m speed were higher (p < 0.05) for the STR group compared with SOC and control groups. The above data show that soccer training alone improves more than normal growth maximum strength of the lower limps and agility. The addition of resistance training, however, improves more maximal strength of the upper and the lower body, vertical jump height, and 30-m speed. Thus, the combination of soccer and resistance training could be used for an overall development of the physical capacities of young boys.

Resistance Exercise Training in Patients with Heart Failure

The utility, safety and physiological adaptations of resistance exercise training in patients with chronic heart failure (CHF) are reviewed and recommendations based on current research are presented. Patients with CHF have a poor clinical status and impaired exercise capacity due to both cardiac limitations and peripheral maladaptations of the skeletal musculature. Because muscle atrophy has been demonstrated to be a hallmark of CHF, the main principle of exercise programmes in such patients is to train the peripheral muscles effectively without producing great cardiovascular stress. For this reason, new modes of training as well as new training methods have been applied. Dynamic resistance training, based on the principles of interval training, has recently been established as a safe and effective mode of exercise in patients with CHF. Patients perform dynamic strength exercises slowly, on specific machines at an intensity usually in the range of 50–60% of one repetition maximum; work phases are of short duration (≤60 seconds) and should be followed by an adequate recovery period (work/recovery ratio >1: 2). Patients with a low cardiac reserve can use small free weights (0.5, 1 or 3kg), elastic bands with 8–10 repetitions, or they can perform resistance exercises in a segmental fashion. Based on recent scientific evidence, the application of specific resistance exercise programmes is safe and induces significant histochemical, metabolic and functional adaptations in skeletal muscles, contributing to the treatment of muscle weakness and specific myopathy occurring in the majority of CHF patients. Increased exercise tolerance and peak oxygen consumption (VO2peak), changes in muscle composition, increases in muscle mass, alterations in skeletal muscle metabolism, improvement in muscular strength and endurance have also been reported in the literature after resistance exercise alone or in combination with aerobic exercise. According to new scientific evidence, appropriate dynamic resistance exercise should be recommended as a safe and effective alternative training mode (supplementary to conventional aerobic exercise) in order to counteract peripheral maladaptation and improve muscle strength, which is necessary for recreational and daily living activities, and thus quality of life, of patients with stable, CHF.

Effects of a Heavy and a Moderate Resistance Training on Functional Performance in Older Adults

Resistance training can improve strength and functional performance, but there is little information about the effect of training intensity on functional performance in older adults. The purpose of this study was to determine the effect of 12 weeks of heavy (80% of 1 repetition maximum [1RM]) and moderate (60% of 1RM) resistance training on functional performance in healthy, inactive older adults, ages 60–74 years. Volunteer subjects were assigned randomly to a control group (CS, n = 10), heavy resistance training group (HRT, n = 11), or moderate resistance training group (MRT, n = 12) and participated in 12 weeks of strength training, 3 times per week. Performance measurements included 1RM lower-body strength, chair-rising time, walking velocity, stair-climbing time, and flexibility. Significant differences between HRT and MRT were found for 1RM strength of the lower limbs after the training period. Functional performance improved similarly for both HRT and MRT after the training period. Functional performance can be improved significantly with either heavy or moderate resistance training, without significant differences in the effectiveness of the 2 training protocols.

Short-term effects of selected exercise and load in contrast training on vertical jump performance.

The present study examined the short-term effects of loaded half squats (HSs) and loaded jump squats (JSs) with low and moderate loads on the squat jump (SJ) and the countermovement jump (CMJ) performance using a contrast training approach. Ten men (mean ± SD age, 23 ± 1.8 years) performed the HS and JS exercises twice with loads of 30% of 1 repetition maximum (1RM) (HS30% and JS30%, respectively) and 60% of 1RM (HS60% and JS60%, respectively). On each occasion, 3 sets of 5 repetitions with 3 minutes of rest were performed as fast as possible. Vertical jump performance was measured before exercise, 1 minute after each set, and at the fifth and 10th minutes of recovery. The CMJ increased significantly after the first and second set (3.9%; p < 0.05) compared with preexercise values following the JS30% protocol and 3.3% after the second and third sets of the JS60% protocol. Following the HS60% protocol, CMJ increased after the first and the second sets (3.6%; p < 0.05) compared with preexercise values, whereas SQ increased only after the first set (4.9%; p < 0.05) in this condition. These data show that contrast loading with the use of low and moderate loads can cause a short-term increase in CMJ performance. The applied loads do not seem to present different short-term effects after loaded JSs. When the classic form of dynamic HS exercise is performed, however, at least a moderate load (60% of 1RM) needs to be applied.

Obesity and physical fitness of pre-adolescent children during the academic year and the summer period: effects of organized physical activity.

This study examined obesity and parameters of physical fitness in 178 elementary schoolchildren during an academic year as well as after the summer holidays. Results showed significant physical fitness improvements during the school year, with little or no changes in the summer holidays. Children who reported less than 30 minutes of daily participation in physical activity demonstrated lower prevalence rates for overweight and obesity as well as superior fitness performance. The detrimental effect of the summer break on the progress of physical fitness was less in children who did participate in physical activity than in those who did not. Longitudinal modelling using generalized estimating equations demonstrated that physical activity is a major contributing factor for obesity over time, masking the singular effect of various fitness parameters. It is concluded that pre-adolescent children advance in physical fitness mainly during the school year, with physical activity being a beneficial countermeasure for the development of obesity.

Failure to obtain a unique threshold on the blood lactate concentration curve during exercise.

Abstract The purpose of this study was to compare various methods and criteria used to identify the anaerobic threshold (AT), and to correlate the AT obtained with each other and with running performance. Furthermore, a number of additional points throughout the entire range of lactate concentrations [La−] were obtained and correlated with performance. A group of 19 runners [mean age 33.7 (SD 9.6) years, height 173 (SD 6.3) cm, body mass 68.3 (SD 5.4) kg, maximal O2 uptake (V˙O2max) 55.2 (SD 5.9) ml · kg−1 · min−1] performed a maximal multistage treadmill test (1 km · h−1 every 3.5 min) with blood sampling at the end of each stage while running. All AT points selected (visual [La−], 4 mmol · l−1 [La−], 1 mmol · l−1 above baseline, log-log breakpoint, and 45° tangent to the exponential regression) were highly correlated one with another and with performance (r > 0.90) even when there were many differences among the AT (P < 0.05). The additional points (ranging from 3 to 8 mmol · l−1 [La−], 1 to 6 mmol · l−1 [La−] above the baseline, and 30 to 70° tangent to the exponential curve of [La−]) were also highly correlated with performance (r > 0.90). These results failed to demonstrate a distinct AT because many points of the curve provided similar information. Intercorrelations and correlations between AT and performance were, however, reduced when AT were expressed as the percentage of maximal treadmill speed obtained at AT or percentage of V˙O2max. This would indicate that different attributes of aerobic performance (i.e. maximal aerobic power, running economy and endurance) are measured when manipulating units. Thus, coaches should be aware of these results when they prescribe an intensity for training and concentrate more on the physiological consequences of a chosen [La−] rather than on a “threshold”.

Training and detraining effects of a combined-strength and aerobic exercise program on blood lipids in patients with coronary artery disease

PURPOSE The aim of this study was to investigate training and detraining effects on blood lipids and apolipoproteins induced by a specific program that combined strength and aerobic exercise in patients with coronary artery disease (CAD). METHODS For this study, 14 patients participated in a supervised 8-month training program composed of two strength sessions (60% of 1 repetition maximum) and two aerobic training sessions (60%-85% of maximum heart rate), and 13 patients served as a control group. Blood samples for total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), apolipoproteins A1 (apo-A1) and B (apo-B), and lipoprotein (a) (Lp[a]) were obtained along with muscular strength at the beginning of the study, after 4 and 8 months of training and after 3 months of detraining. RESULTS The patients in the intervention group showed favorable alterations after 8 months of training (TC, -9.4; TG, -18.6; HDL-C, 5.2; apo-A1, 11.2%; P <.05), but these were reversed after 3 months of detraining (TC, +3.7; TG, 16.1; HDL-C, -3.6; apo-A1, -5.5%). In addition, body strength also improved after training (27.8%) but reversed (-12.9%) after detraining (P <.05). The patients in the control group did not experience any significant alterations. CONCLUSIONS The results indicate that an 8-month training program combining strength and aerobic exercise induces favorable muscular and biochemical adaptations, on TC, TG, HDL-C, and apo-A1 levels, protecting patients with CAD. After 3 months of detraining, however, the favorable adaptations were reversed, underscoring the need of uninterrupted exercise throughout life.

Test-retest reliability of the eurofit test battery administered to university students

The purpose of this study was to examine the rest-retest reliability of the Eurofit motor fitness tests performed by university students. A total of 98 undergraduate students who were enrolled in physical education departments in Greece participated (29 men aged 19.5 ± 2.7 hr. and 66 women aged 19, 4 ± 2.7 yr.). ALL Eurofit motor fitness tests and anthropometric measurements were obtained twice with one week between the two measurements, Intraclass correlation coefficient indicated satisfactory coefficients above .70 for most tests. The only exception was the plate-tapping test which yielded a low value (R = .57). Further, the majority of the Eurofit test battery fitted well within the 95% confidence interval, and only three Eurofit motor fitness test items (flamingo balance, plate tapping, and sit-ups) presented a confidence limit below the value of .70, These findings indicated that the Eurofit test battery yielded reliable data for undergraduate students. However, modifications should be considered to improve the reliability of certain test items, for application to undergraduates.

Acute and chronic effects of exercise on circulating endothelial progenitor cells in healthy and diseased patients.

Exercise is known to improve endothelial function in healthy subjects as well as patients with cardiovascular disease and this might be partially related to a regeneration of diseased endothelium by circulating progenitor cells (EPCs). EPCs are a subgroup of peripheral blood monocytes that contribute to re-endothelialization of injured endothelium as well as neovascularization of ischemic lesions. Cross-sectional studies have indicated that chronic, regular physical activity has a positive effect on the levels of circulating EPCs. This is associated with an improvement of endothelial dysfunction that is induced by apoptosis due to the underlying aging process or accelerated by cardiovascular risk factors. Furthermore, it is well established that chronic exercise training has the potency to mobilize EPCs from the bone marrow. For patients with cardiac disease this is of clinical importance since EPCs have been implicated in vascular repair and revascularization. Studies are needed to refine the best mode of exercise training that will upregulate circulating EPCs as well as to clarify the kinetics of EPCs after the termination of different exercise sessions in different diseases and medication. Whether there is a direct link between enhanced mobilization of EPCs via exercise and improvement of disease and prognosis remains a hypothesis which needs to be further evaluated.