The purpose of this study was to investigate the effects of a 12-week resistance-training program on muscle strength and mass in older adults. Thirty-three inactive participants (60–74 years old) were assigned to 1 of 3 groups: high-resistance training (HT), moderate-resistance training (MT), and control. After the training period, both HT and MT significantly increased 1-RM body strength, the peak torque of knee extensors and flexors, and the midthigh cross-sectional area of the total muscle. In addition, both HT and MT significantly decreased the abdominal circumference. HT was more effective in increasing 1-RM strength, muscle mass, and peak knee-flexor torque than was MT. These data suggest that muscle strength and mass can be improved in the elderly with both high- and moderate-intensity resistance training, but high-resistance training can lead to greater strength gains and hypertrophy than can moderate-resistance training.
Vasilios I. Kalapotharakos, Maria Michalopoulou, George Godolias, Savvas P. Tokmakidis, Paraskevi V. Malliou and Vasilios Gourgoulis
Olivier Galy, Laurent Maimoun, Olivier Coste, Jérôme Manetta, Alain Boussana, Christian Préfaut and Olivier Hue
Postexercise alveolar-capillary membrane-diffusing capacity (DLco) often decreases in highly trained endurance athletes and seems linked to their training status. To test the hypothesis that training status influences postexercise DLco, 13 male and 2 female triathletes (20.2 ± 4.4 y old, 175.2 ± 6.7 cm tall; weight in a range of 66.6 ± 7.4 kg to 67.4 ± 7.8 kg during the 1-y study) were randomized into experimental (n = 7) and control (n = 8) groups and performed VO2max cycle tests and simulated cycle-run successions (CR) of 30 min + 20 min after 3 periods in the competitive season.
Both groups were tested before (pre- HTP) and after a 30-wk high-training period (HTP) with high training volume, intensity, and frequency. The experimental group was then also tested after a 6-wk low-training period (LTP) with low training volume, intensity, and frequency, while the control group continued training according to the HTP schedule for these 6 wk. Ventilatory data were collected continuously. DLco testing was performed before and 30, 60, and 120 min after the CR trials.
Whatever the period or group, DLco was significantly decreased 30 min after CR, with a significantly greater decrease in the experimental group than the control group in LTP (−15.7% and –9.3% of DLco, respectively).
Six weeks of low training volume and intensity were sufficient to reverse the effects of high training volume and intensity on the alveolar-capillary membrane after a CR succession in competitive triathletes.
Miguel David Ferrer, Pedro Tauler, Antoni Sureda, Pedro Pujol, Franchec Drobnic, Josep Antoni Tur and Antoni Pons
Soccer-associated oxidative stress has barely been studied. The aims of this study were to establish the effect of a soccer training match and the effect of a diet supplementation with a multivitamin complex and coenzyme Q during 3 months of soccer training on the pro-oxidant and antioxidant status of lymphocytes. In a randomized, double-blind trial, 19 male preprofessional soccer players were treated with either an antioxidant nutrient cocktail or placebo for 90 days. After this period the athletes played a soccer match lasting 60 min. All determinations were made under basal conditions before and after the training period and after the match. Basal lymphocyte hydrogen peroxide (H2O2) production did not change after the 3 months of training. Catalase activity decreased (about 50%) after the 3 months, whereas glutathione reductase increased its activity (150–200%) both with placebo and in the supplemented group. Basal ascorbate levels were maintained during the training period, whereas α-tocopherol and MDA decreased (about 40%) in both groups. The match increased H2O2 production (180%) in both groups when the lymphocytes were stimulated with phorbol myristate acetate, and it also increased MDA levels (150%). Antioxidant enzyme activities and antioxidant vitamin levels were maintained before and after the match. Regular soccer training modifies the lymphocyte strategy to eliminate ROS and increases protection against oxidative damage. A friendly soccer match raises lymphocyte capacity to produce ROS and oxidative damage, but it is not enough to induce a defensive response, thus leading to a situation of postexercise oxidative stress. Supplementation with low doses of antioxidant vitamins and coenzyme Q does not modify the endogenous antioxidant response to training.
Yann Le Meur, Martin Buchheit, Anaël Aubry, Aaron J Coutts and Christophe Hausswirth
Faster heart-rate recovery (HRR) after high to maximal exercise (≥90% of maximal heart rate) has been reported in athletes suspected of functional overreaching (f-OR). This study investigated whether this response would also occur at lower exercise intensity.
Responses of HRR and rating of perceived exertion (RPE) were compared during an incremental intermittent running protocol to exhaustion in 20 experienced male triathletes (8 control subjects and 13 overload subjects led to f-OR) before and immediately after an overload training period and after a 1-wk taper.
Both groups demonstrated an increase in HRR values immediately after the training period, but this change was very likely to almost certainly larger in the f-OR group at all running intensities (large to very large differences, eg, +16 ± 7 vs +3 ± 5 beats/min, in the f-OR and control groups at 11 km/h, respectively). The highest between-groups differences in changes in HRR were reported at 11 km/h (13 ± 4 beats/min) and 12 km/h (10 ± 6 beats/min). A concomitant increase in RPE at all intensities was reported only in the f-OR group (large to extremely large differences, +2.1 ± 1.5 to +0.7 ± 1.5 arbitrary units).
These findings confirm that faster HRR does not systematically predict better physical performance. However, when interpreted in the context of the athletes’ fatigue state and training phase, HRR after submaximal exercise may be more discriminant than HRR measures taken after maximal exercise for monitoring f-OR. These findings may be applied in practice by regularly assessing HRR after submaximal exercise (ie, warm-up) for monitoring endurance athletes’ responses to training.
Rebecca T. Viner, Margaret Harris, Jackie R. Berning and Nanna L. Meyer
The purpose of this study was to assess energy availability (EA) and dietary patterns of 10 adult (29–49 years) male (n = 6) and female (n = 4) competitive (USA Cycling Category: Pro, n = 2; 1–4, n = 8) endurance cyclists (5 road, 5 off-road), with lower than expected bone mineral density (BMD; Z score < 0) across a season. Energy intake (EI) and exercise energy expenditure during preseason (PS), competition (C), and off-season (OS) were estimated from 3-day dietary records, completed once per month, across a cycling season. BMD was measured by DXA at 0 months/5 months/10 months. The Three-Factor Eating Questionnaire (TFEQ) was used to assess cognitive dietary restraint. Seventy percent of participants had low EA [(LEA); < 30 kcal·kg fat-free mass (FFM)−1·day−1] during PS, 90% during C, and 80% during OS (range: 3–37 kcal·kg FFM−1·day−1). Ninety percent of cyclists had LEA during ≥ 1 training period, and 70% had LEA across the season. Seventy percent of cyclists were identified as restrained eaters who consciously restrict EI as a means of weight control. Mean daily carbohydrate intake was below sport nutrition recommendations during each training period (PS: 3.9 ± 1.1 g·kg−1·day−1, p < .001; C: 4.3 ± 1.4 g·kg−1·day−1, p = .005; OS: 3.7 ± 1.4 g·kg−1·day−1, p = .01). There were no differences in EA and EI·kg−1 between male and female cyclists and road and off-road cyclists. Low EI, and specifically low carbohydrate intake, appears to be the main contributor to chronic LEA in these cyclists. Adult male and female competitive road and off-road cyclists in the United States may be at risk for long-term LEA. Further studies are needed to explore strategies to prevent and monitor long-term LEA in these athletes.
Crayton L. Moss and Scott Grimmer
The purpose of this study was to determine whether twitch contractile properties and strength of the triceps surae could be altered by 8 weeks of low-repetition or high-repetition isotonic exercise. Subjects were randomly assigned to either the low- or high-repetition group. Before- and after-training measurements were recorded for strength and contractile properties. The contractile variables of the muscle twitch were latency, time to peak force, peak force, half-contraction time, and half-relaxation time. Strength measurements were determined utilizing a one repetition maximal (1-RM) heel-raise testing device. A two-way ANOVA with repeated measures was used to test the effect of training on each variable. Both groups showed a significant increase in 1-RM and half-relaxation time and a decrease in electrical stimulation current after the 8-week training period. It was concluded that if high-repetition exercises develop slow-twitch Type I muscle fibers and low-repetition exercises develop fast-twitch Type II fibers, training programs must be designed specifically according to the desired outcome.
Judith A. Siegel, David N. Camaione and Thomas G. Manfredi
To assess the effects of a group resistance exercise program on prepubescent children, an experimental group of boys (n = 26) and girls (n = 24), with a mean age of 8.4 ± 0.5 years, participated in 12 weeks of school based training. The program consisted of upper body exercise using hand-held weights, stretch tubing, balls, and self-supported movements. A control group of boys (n = 30) and girls (n = 16), mean age 8.6 ± 0.5 years, had a free-play period. Boys were significantly stronger than girls on all initial strength evaluations and were taller and had lesser skinfold sums. ANCOVA was used to evaluate pre/post changes in cable tensiometer elbow flexion and extension, right and left handgrip strength, pull-ups, flexed arm hang, sit-ups, sit-and-reach flexibility, and body composition parameters. Following the training period, significantly greater gains were made by the experimental group for right handgrip, flexed arm hang, pull-ups, and flexibility. Greater decreases in sum of skinfolds were also found. Training responses of boys and girls were similar. It was concluded that a group strength training program can be an effective means of increasing fitness levels and improving body composition in both boys and girls of this age.
Ro Di Brezzo, Inza L. Fort and George L. Hoyt III
The purpose of this study was to examine the effects of training two times per week versus three times per week on strength development in older women. Subjects were 59 women between the ages of 40 and 65 years. Variables measured were body weight, percent fat, girth, flexibility, and strength one-repetition maximums (1RM). Subjects were randomly assigned to one of two training groups: twice a week (2x) or three times a week (3x). Total training volume for the two groups was approximately equal and the training period lasted eight weeks. Pre-to-post results were analyzed within and between groups. Both training protocols were effective for reducing body fat and increasing strength as measured by the 1RM. The 3x group showed greater gains in increasing 1RMs in the Standing Lat Pull, Triceps Extension, and Leg Press. Most girth measurements in both groups did not significantly change, but both groups increased flexibility. In an age when time demands on women are increasing, resistive training two times a week is effective for producing strength gains.
Eszter Csajági, Ipoly Szauder, Zsuzsanna Major and Gábor Pavlik
Training adaptation of the left ventricle (LV) and it’s reversibility following the cessation of training in adults is well known and also studied in children. In the current study we describe the changes in the LV morphology in association with the training season during a 1.5 year follow-up period. 15 elite adolescent swimmers, seven girls and 8 boys with 6 years of swimming history and 20 hr per week training were observed. Their data were compared with 15 age and gender matched nonathletes. LV adaptation was measured with 2D-echocardiography at the baseline preseason and every 3 months, according to the macro cyclic periods of training. Nonathletes were observed at the first and fifth stage of the study. Remarkable LV morphological adaptation has been detected in the swimmers. The greatest LV muscle mass (LVMM: 228 ± 46g) and smallest end-diastolic diameter (LVIDd:44.9 ± 3.4mm) were observed at the end of the second general endurance preparation period (GEP2), but the LVMM/BSA3/2 (Rel.LVMM: 85 ± 10g/m) failed to change during the follow-up in athletes. On the basis of our results, we suggest comparing absolute LV dimensions only in studies made at the same training period to avoid bias due to alterations with the training season.
Ryan J. Hamilton, Carl D. Paton and William G. Hopkins
In a recent study competitive road cyclists experienced substantial gains in sprint and endurance performance when sessions of high-intensity interval training were added to their usual training in the competitive phase of a season. The current study reports the effect of this type of training on performance of 20 distance runners randomized to an experimental or control group for 5 to 7 weeks of training. The experimental group replaced part of their usual competitive-phase training with 10 × 30-minute sessions consisting of 3 sets of explosive single-leg jumps (20 for each leg) alternating with 3 sets of resisted treadmill sprints (5 × 30-second efforts alternating with 30-second recovery). Before and after the training period all runners completed an incremental treadmill test for assessment of lactate threshold and maximum running speed, 2 treadmill runs to exhaustion for prediction of 800- and 1500-m times, and a 5-km outdoor time trial. Relative to the control group, the mean changes (±90% confidence limits) in the experimental group were: maximum running speed, 1.8% (± 1.1%); lactate-threshold speed, 3.5% (±3.4%); predicted 800-m speed, 3.6% (± 1.8%); predicted 1500-m speed, 3.7% (± 3.0%); and 5-km time-trial speed, 1.2% (± 1.1%). We conclude that high-intensity resistance training in the competitive phase is likely to produce beneficial gains in performance for most distance runners.