Maximal strength training improves running economy in distance runners

PURPOSE: The present study investigated the effect of maximal strength training on running economy (RE) at 70% of maximal oxygen consumption [formula: see text] and time to exhaustion at maximal aerobic speed (MAS). Responses in one repetition maximum (1RM) and rate of force development (RFD) in half-squats, maximal oxygen consumption, RE, and time to exhaustion at MAS were examined. METHODS: Seventeen well-trained (nine male and eight female) runners were randomly assigned into either an intervention or a control group. The intervention group (four males and four females) performed half-squats, four sets of four repetitions maximum, three times per week for 8 wk, as a supplement to their normal endurance training. The control group continued their normal endurance training during the same period. RESULTS: The intervention manifested significant improvements in 1RM (33.2%), RFD (26.0%), RE (5.0%), and time to exhaustion at MAS (21.3%). No changes were found in [formula: see text] or body weight. The control group exhibited no changes from pre to post values in any of the parameters. CONCLUSION: Maximal strength training for 8 wk improved RE and increased time to exhaustion at MAS among well-trained, long-distance runners, without change in maximal oxygen uptake or body weight.     

Maximal strength training improves work economy in trained female cross-country skiers.

PURPOSE: The present study examines the hypothesis that maximal strength training improves work economy and anaerobic threshold in trained female cross-country skiers while working on a ski ergometer. METHODS: Fifteen female cross-country skiers (17.9 +/- 0.3 yr, 166.7 +/- 1.3 cm, 60.1 +/- 1.9 kg, and 55.3 +/- 1.3 mL x kg(-1) x min(-1)) participated in the study. Eight skiers made up the high-intensity strength-trained group, and seven served as the control group. Endurance performance was tested on a specially instrumented ski ergometer. Strength training and testing simulated double poling in cross-country skiing. RESULTS: A significant (P < 0.001) improvement in double-poling economy on the ski ergometer was observed among the strength-trained group. Anaerobic threshold did not change during the experimental period for either group. After a 9-wk training period, time to exhaustion increased from 5.2 (+/-0.9) to 12.3 (+/-1.6) min (P < 0.001) and from 4.0 (+/-0.9) to 6.3 (+/-0.9) min (P < 0.01) for the strength and control group, respectively. Time to exhaustion was significantly higher (P < 0.001) for the strength group compared with the control group after training. One repetition maximum increased 14.5% (1.8) (P < 0.001) in the strength group but was unchanged in the control group. Expressed in relation to peak force at one repetition maximum, strength training resulted in a significant reduction in the relative available force employed working on the ski ergometer (P < 0.01). Time to peak force at maximal aerobic velocity on the ski ergometer was significantly reduced in the strength-training group (P < 0.01). CONCLUSIONS: It is concluded that maximal strength training in the upper-body improved the double-poling performance by improved work economy. Work economy was improved by a reduction in relative workload and time to peak force while double poling.     

Branched-chain amino acid supplementation improves cycling performance in untrained cyclists

ObjectivesTo investigate the effects of acute branched-chain amino acid (BCAA) supplementation on cycling performance and neuromuscular fatigue during a prolonged, self-paced cycling time-trial.DesignRandomised double-blind counterbalanced crossover.MethodsEighteen recreationally active men (mean ± SD; age: 24.7 ± 4.8 years old; body-weight, BW: 67.1 ± 6.1 kg; height: 171.7 ± 4.9 cm) performed a cycling time-trial on an electromagnetically-braked cycle ergometer. Participants were instructed to complete the individualised total work in the shortest time possible, while ingesting either BCAAs (pre-exercise: 0.084 g kg^?1 BW; during exercise: 0.056 g kg^?1 h^?1) or a non-caloric placebo solution. Rating of perceived exertion, power, cadence and heart rate were recorded throughout, while maximal voluntary contraction, muscle voluntary activation level and electrically evoked torque using single and doublet stimulations were assessed at baseline, immediately post-exercise and 20-min post-exercise.ResultsSupplementation with BCAA reduced (287.9 ± 549.7 s; p = 0.04) time-to-completion and ratings of perceived exertion (p ≤ 0.01), while concomitantly increasing heart rate (p = 0.02). There were no between-group differences (BCAA vs placebo) in any of the neuromuscular parameters, but significant decreases (All p ≤ 0.01) in maximal voluntary contraction, muscle voluntary activation level and electrically evoked torque (single and doublet stimulations) were recorded immediately following the trial, and these did not recover to pre-exercise values by the 20 min recovery time-point.ConclusionsCompared to a non-caloric placebo, acute BCAA supplementation significantly improved performance in cycling time-trial among recreationally active individuals without any notable changes in either central or peripheral factors. This improved performance with acute BCAA supplementation was associated with a reduced rating of perceived exertion.     

Strength training improves cycling performance,fractional utilization of VO2max and cycling economy in female cyclists

The purpose of this study was to investigate the effect of adding heavy strength training to well‐trained female cyclists’ normal endurance training on cycling performance. Nineteen female cyclists were randomly assigned to 11 weeks of either normal endurance training combined with heavy strength training (E+S, n = 11) or to normal endurance training only (E, n = 8). E+S increased one repetition maximum in one‐legged leg press and quadriceps muscle cross‐sectional area (CSA) more than E (P < 0.05), and improved mean power output in a 40‐min all‐out trial, fractional utilization of VO_2max and cycling economy (P < 0.05). The proportion of type IIAX‐IIX muscle fibers in m. vastus lateralis was reduced in E+S with a concomitant increase in type IIA fibers (P < 0.05). No changes occurred in E. The individual changes in performance during the 40‐min all‐out trial was correlated with both change in IIAX‐IIX fiber proportion (r = ?0.63) and change in muscle CSA (r = 0.73). In conclusion, adding heavy strength training improved cycling performance, increased fractional utilization of VO_2max, and improved cycling economy. The main mechanisms behind these improvements seemed to be increased quadriceps muscle CSA and fiber type shifts from type IIAX‐IIX toward type IIA.     

Maximal strength training improves aerobic endurance performance

The aim of this experiment was to examine the effects of maximal strength training with emphasis on neural adaptations on strength- and endurance-performance for endurance trained athletes. Nineteen male cross-country skiers about 19.7 +/- 4.0 years of age and a maximal oxygen uptake (VO(2 max)) of 69.4 +/- 2.2 mL x kg(-1) x min(-1) were randomly assigned to a training group (n = 9) or a control group (n = 10). Strength training was performed, three times a week for 8 weeks, using a cable pulley simulating the movements in double poling in cross-country skiing, and consisted of three sets of six repetitions at a workload of 85% of one repetition maximum emphasizing maximal mobilization of force in the concentric movement. One repetition maximum improved significantly from 40.3 +/- 4.5 to 44.3 +/- 4.9 kg. Time to peak force (TPF) was reduced by 50 and 60% on two different submaximal workloads. Endurance performance measured as time to exhaustion (TTE) on a double poling ski ergometer at maximum aerobic velocity, improved from 6.49 to 10.18 min; 20.5% over the control group. Work economy changed significantly from 1.02 +/- 0.14 to 0.74 +/- 0.10 mL x kg(-0.67) x min(-1). Maximal strength training with emphasis on neural adaptations improves strength, particularly rate of force development, and improves aerobic endurance performance by improved work economy.     

Effect of acute moderate aerobic cycling on systemic inflammatory responses in young untrained men

Objectives

There is evidence to suggest that exercising can induce an inflammatory response. The present study was conducted to determine the effect of a fixed period of acute moderate cycling on systemic inflammatory responses in young untrained men.

Methods

This quasi-experimental pre-post design study was carried out on 10 young, healthy, untrained men. One week after preliminary measures were recorded, the subjects participated in an acute moderate cycling protocol (45 min with 50% VO_2max). Complete blood cell counts, fasting blood glucose, serum interleukin-6, interleukin-10, C-reactive protein and plasma cortisol and epinephrine were analyzed.

Results

Total and differential circulating leukocyte counts increased immediately after acute moderate cycling. In addition, serum interleukin-6, interleukin-10 and C-reactive protein concentrations, and plasma levels of epinephrine and cortisol increased immediately after exercise (P < 0.005). Furthermore, there was a positive and significant correlation between the post-exercise total leukocyte counts and serum interleukin-10 levels (P = 0.021). Surprisingly, correlations between exercise-induced reduced fasting blood glucose levels, total leukocyte counts and serum C-reactive protein and interleukin-6 levels after exercise were not significant (P > 0.05).

Conclusion

Moderate exercise is not sufficient to induce immunological stress/reactions in healthy individuals.     

Skeletal muscle and hormonal adaptations to circuit weight training in untrained men

Twelve men either performed 10 weeks of timed circuit weight training 3 days week(-1) (CWT; n=8; X+/-SE; age=23.6+/-1.8 years), or were part of a sedentary control group (n=4; age=20.5+/-1.0 years). Significance was P<0.05 for all analyses. The CWT program significantly increased 1 repetition maximum (1 RM) strength for nine of 10 exercises (15-42%). Although no body composition measure significantly changed for the CWT group, low-to-moderate effect sizes were evident for body weight, lean body mass, and relative fat. CWT did not alter percent fiber type, but did increase cross-sectional areas for type IIA fibers (microm(2); pre=5988+/-323, post=7259+/-669). Relative (%) myosin heavy-chain (MHC) expression increased for MHC IIa (pre=42.5+/-2.7, post=50.1+/-2.6), and decreased for MHC IIb (pre=21.8+/-2.8, post=15.4+/-2.4) for the CWT group. Serum testosterone, cortisol, and the testosterone/cortisol ratio did not change at any time for the CWT group. None of the measured variables changed for the control group. These data indicate that for untrained subjects, CWT of the type used resulted in improved muscular strength and a tendency toward increased lean mass. Compared with other types of weight training, fewer adaptations of the muscle fibers were evident. This is likely due in part to the relatively low loads used with this type of resistance exercise.     

Maximal strength training improves walking performance in peripheral arterial disease patients

Peripheral arterial disease (PAD) patients have reduced muscle strength and impaired walking ability. The aim of this study was to examine the effects of maximal strength training (MST) on walking economy and walking performance in PAD patients. Ten patients with mild to moderate‐severe claudication, classified as Fontaine stage II PAD and with functional limitations from intermittent claudication were recruited and went through an 8‐week control period followed by an 8‐week, three times a week, MST period. The patients performed four sets of five repetitions dynamic leg press with emphasis on maximal mobilization of force in the concentric action and with a progressive adjusted intensity corresponding to 85–90% of one repetition maximum (1 RM). After the MST period, leg press 1 RM significantly increased by 35.0±10.8 kg (31.3%). Dynamic rate of force development, measured on a force plate installed on the leg press, increased by 1424±1217 N/s (102.7%). The strength improvements led to a significant increase in walking economy of 9.7% when walking horizontally, and to a significant increase in walking performance of 13.6% measured on an incremental treadmill test to exhaustion. No changes were apparent after the control period. No changes in body mass or peak oxygen uptake were observed. MST increases strength in Fontaine stage II PAD patients and leads to improved walking economy. These results suggest that application of MST could accompany aerobic endurance training as a part of the treatment of PAD patients with mild to moderate‐severe claudication.     

Neuromuscular and cardiovascular adaptations during concurrent strength and endurance training in untrained men

This study examined the effects of concurrent strength and endurance training on neuromuscular and endurance characteristics compared to strength or endurance training alone. Previously untrained men were divided into strength (S: n=16), endurance (E: n=11) or concurrent strength and endurance (SE: n=11) training groups. S and E trained 2 times and SE 2 + 2 times a week for strength and endurance during the 21-week period. Maximal unilateral isometric and bilateral concentric forces of leg muscles increased similarly in S and SE by 20-28% (p<0.01) and improvements in isometric forces were accompanied by increases (p<0.05) of maximal muscle activation. Rate of force development of isometric action (p<0.05) improved only in S. The increase in muscle cross-sectional area of the quadriceps femoris in SE (11%, p<0.001) were greater than in S (6%, p<0.001) or in E (2%, p<0.05). SE and E increased maximal cycling power (SE: 17% and E: 11%, p<0.001) and VO2MAX (SE: 17%, p<0.001 and E: 5%, ns.). These results suggest that the present moderate volume 21-week concurrent SE training in previously untrained men optimizes the magnitude of muscle hypertrophy, maximal strength and endurance development, but interferes explosive strength development, compared with strength or endurance training alone.     

Recreational soccer training improves heart-rate variability indices and physical performance in untrained healthy adolescent

The aim of this study was to evaluate the effects of soccer training on short-term heart-rate variability, blood pressure, and physical fitness in untrained healthy adolescents. Twenty-two adolescent boys took part in this study: 11 boys were randomly assigned to participate in an 8-week soccer training and 11 boys served as a control group. Soccer exhibited significant increases in high-frequency power (difference 52.9%, P = 0.03, effect size: ES = 1.2), root mean squared of the standard deviation rMSSD (10.8%, P = 0.02, ES = 1), and a significant decrease in sympathetic activity LF (26.3%, P = 0.004, ES = 1.4). The control group showed an increase in rMSSD (9.4%, P = 0.05, ES = 1). The soccer group showed increases in estimated aerobic fitness (30.9%, P = 0.001, ES = 1.50) and 20-m sprint performance (4.1%, P = 0.004, ES = 0.8) with a trend to an improvement in horizontal jumping (3.8%, P = 0.15, ES = 0.8). In conclusion, soccer-based training improved measures of both physical fitness and autonomic function making soccer an effective training strategy for improving health-related fitness measures in untrained adolescents.     

A 4-week endurance training program improves tolerance to mental exertion in untrained individuals

ObjectivesThe aim of this study was to investigate whether 4 weeks of endurance training could improve tolerance to mental exertion in untrained participants.DesignLongitudinal training study.MethodsTwenty untrained young adults (14 F, 6 M; 27.6 ± 6.2 years) completed a 4-week training protocol in a randomised and counterbalanced order. Baseline and follow-up assessment were conducted over three sessions in the week preceding and following the training period. During session 1, participants completed an incremental maximal ramp test. During sessions 2 and 3 participants completed a 15 min cycling time trial preceded by either a mental exertion or control conditions. Following baseline assessments, participants were randomised into a physical training or placebo group that completed the training intervention thrice weekly over four weeks.ResultsThe physical training resulted in increase in VO₂ peak relative to the placebo group (p = 0.003). Linear Mixed Models utilising the control condition time trial performance as a covariate found the physical training group increased their time trial distance following the mental exertion condition to a greater extent than the placebo group (p = 0.03). RPE during the time trial and perceptual measures of mental exertion did not significantly change between groups (all p > 0.10) although interaction effects were observed when considering the RPE-power output relationship during the time trial.ConclusionsFour weeks of endurance training increased tolerance to mental exertion in untrained participants during a subsequent physical performance, but not during prolonged cognitive performance. This finding suggests that the ability to tolerate mental exertion is trainable in at least some contexts and highlights the far-reaching benefits of endurance training.     

Effects of photobiomodulation associated with endurance running training on oxidative stress in untrained men

Purpose

This study examined the effects of photobiomodulation (PBM) associated with endurance running training on oxidative stress (OS) markers in untrained men.

Methods

Thirty untrained men distributed into a placebo group (PLA) or PBM group (PBMG) performed 8 weeks of running training, in which the PBMG had the LED application before all training sessions. The PBM was performed by LED application using an equipment with 56 diodes of red light (660 nm) and 48 diodes of infrared light (850 nm) with an energy dose of 60 J on each of the 5 points. The application was done in two regions of the quadriceps muscle, two regions of the biceps femoris, and one region of the gastrocnemius muscle in both legs. The assessments were performed at pre- and post-training, and the OS markers analyzed were malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH) and oxidized (GSSG).

Results

PBM associated with running training did not significantly affect the OS markers CAT, SOD, MDA, GSH, and reduced GSH/GSSG responses after training. GSSG levels decreased in the PBMG and increased in the PLA, with significant difference between the % change values (??13.5?±?30.3% vs. 56.3?±?83.4%; P?=?0.043).

Conclusions

Therefore, PBM associated with endurance running training did not significantly affect CAT, SOD, MDA, reduced GSH, and reduced GSH/GSSG ratio post-training; however, the GSSG increased in PLA group and decreased in PBMG, indicating a positive effect of the PBM in this marker of OS.

     

The effects of dietary nitrate supplementation on the adaptations to sprint interval training in previously untrained males

Objectives

Dietary nitrate can improve repeated high-intensity and supramaximal exercise performance, although the effect on adaptations to training has received limited attention. The purpose of this study was to investigate the effects of dietary nitrate on the response to 3-weeks of sprint interval training (SIT).

Resistance training improves glycaemic control in obese type 2 diabetic men

The purpose of this investigation was to determine whether moderate intensity resistance training (RT) improves glycaemic control in obese, type 2 diabetic men. Eighteen subjects were randomly assigned to a 10-week RT program, or a non-training control group (C). Glycosylated haemoglobin (HbA 1c ), fasting glucose and insulin, glucose and insulin 120 minutes (2h) after a 75 g oral glucose load, body composition and muscular strength and endurance were measured before and after the 10-week experimental period. In the RT group fasting glucose and insulin decreased with training (p < 0.05) and decreases in HbA 1c approached significance (p = 0.057). 2-h glucose and insulin did not change in either group. Fat free mass (FFM) increased by 3.5 % after RT but was unchanged in the controls. Fat mass (FM) increased 6.9 % in C but was unchanged in RT. Percent body fat was unchanged in both groups. Muscular strength and endurance increased by 25 to 52 % in the RT group but was unchanged in controls. Changes in fasting glucose and HbA 1c were inversely related to changes in FFM. These results suggest that RT is an effective form of exercise training which modestly improves glycaemic control and lowers fasting insulin levels in obese type 2 diabetics.     

Maximal inspiratory pressure following maximal exercise in trained and untrained subjects

Previous investigators have demonstrated that 5-10 min of fatiguing exercise would lead to respiratory muscle fatigue in normal subjects. The purpose of this study was to determine if there was a differential inspiratory pressure response to maximal cycle ergometer exercise in trained and untrained subjects. Six highly trained cross country skiers and five untrained college students were studied prior to and 10, 60, and 120 s postexercise (incremental VO2max to exhaustion). On each occasion, maximal inspiratory pressure (MIP) was measured at the mouth from residual volume. Prior to exercise, the two groups had similar MIP values. After exercise, the sedentary subjects experienced significant decreases in MIP compared to the preexercise values. These decreases averaged 10%, 17%, and 13% at 10, 60, and 120 s postexercise, respectively. The skiers, on the other hand, showed no evidence of a decrease in MIP postexercise, with the postexercise values being slightly, but not significantly, higher than the preexercise values. From these results, we conclude that maximal exercise results in inspiratory muscle dysfunction in normal subjects but not in athletes training at or near elite levels. Thus, it appears that endurance exercise training induces an adaptive change in the inspiratory muscles that protects them from the acute loss of strength seen following exercise in normal subjects.