Effect of heavy strength training on thigh muscle cross-sectional area, performance determinants, and performance in well-trained cyclists

Heavy strength training improves running and cycling performance following prolonged submaximal work in well-trained female athletes

The purpose of this study was to investigate the effects of adding heavy strength training to female duathletes' normal endurance training on both cycling and running performance. Nineteen well‐trained female duathletes (VO_2max cycling: 54 ± 3 ml∙kg⁻¹∙min⁻¹, VO_2max running: 53 ± 3 ml∙kg⁻¹∙min⁻¹) were randomly assigned to either normal endurance training (E, n = 8) or normal endurance training combined with strength training (E+S, n = 11). The strength training consisted of four lower body exercises [3 × 4‐10 repetition maximum (RM)] twice a week for 11 weeks. Running and cycling performance were assessed using 5‐min all‐out tests, performed immediately after prolonged periods of submaximal work (3 h cycling or 1.5 h running). E+S increased 1RM in half squat (45 ± 22%) and lean mass in the legs (3.1 ± 4.0%) more than E. Performance during the 5‐min all‐out test increased in both cycling (7.0 ± 4.5%) and running (4.7 ± 6.0%) in E+S, whereas no changes occurred in E. The changes in running performance were different between groups. E+S reduced oxygen consumption and heart rate during the final 2 h of prolonged cycling, whereas no changes occurred in E. No changes occurred during the prolonged running in any group. Adding strength training to normal endurance training in well‐trained female duathletes improved both running and cycling performance when tested immediately after prolonged submaximal work.

Bilateral extracephalic transcranial direct current stimulation improves endurance performance in healthy individuals

BACKGROUND

Transcranial direct current stimulation (tDCS) has been used to enhance endurance performance but its precise mechanisms and effects remain unknown.

OBJECTIVE

To investigate the effect of bilateral tDCS on neuromuscular function and performance during a cycling time to task failure (TTF) test.

METHODS

Twelve participants in randomized order received a placebo tDCS (SHAM) or real tDCS with two cathodes (CATHODAL) or two anodes (ANODAL) over bilateral motor cortices and the opposite electrode pair over the ipsilateral shoulders. Each session lasted 10 min and current was set at 2 mA. Neuromuscular assessment was performed before and after tDCS and was followed by a cycling time to task failure (TTF) test. Heart rate (HR), ratings of perceived exertion (RPE), leg muscle pain (PAIN) and blood lactate accumulation (ΔB[La^-]) in response to the cycling TTF test were measured.

RESULTS

Corticospinal excitability increased in the ANODAL condition (P < 0.001) while none of the other neuromuscular parameters showed any change. Neuromuscular parameters did not change in the SHAM and CATHODAL conditions. TTF was significantly longer in the ANODAL (P = 0.003) compared to CATHODAL and SHAM conditions (12.61 ± 4.65 min; 10.61 ± 4.34 min; 10.21 ± 3.47 min respectively), with significantly lower RPE and higher ΔB[La^-] (P < 0.001). No differences between conditions were found for HR (P = 0.803) and PAIN during the cycling TTF test (P = 0.305).

CONCLUSION

Our findings demonstrate that tDCS with the anode over both motor cortices using a bilateral extracephalic reference improves endurance performance.

Concurrent exercise training: do opposites distract?

Specificity is a core principle of exercise training to promote the desired adaptations for maximising athletic performance. The principle of specificity of adaptation is underpinned by the volume, intensity, frequency and mode of contractile activity and is most evident when contrasting the divergent phenotypes that result after undertaking either prolonged endurance or resistance training. The molecular profiles that generate the adaptive response to different exercise modes have undergone intense scientific scrutiny. Given divergent exercise induces similar signalling and gene expression profiles in skeletal muscle of untrained or recreationally active individuals, what is currently unclear is how the specificity of the molecular response is modified by prior training history. The time course of adaptation and when 'phenotype specificity' occurs has important implications for exercise prescription. This context is essential when attempting to concomitantly develop resistance to fatigue (through endurance-based exercise) and increased muscle mass (through resistance-based exercise), typically termed 'concurrent training'. Chronic training studies provide robust evidence that endurance exercise can attenuate muscle hypertrophy and strength but the mechanistic underpinning of this 'interference' effect with concurrent training is unknown. Moreover, despite the potential for several key regulators of muscle metabolism to explain an incompatibility in adaptation between endurance and resistance exercise, it now seems likely that multiple integrated, rather than isolated, effectors or processes generate the interference effect. Here we review studies of the molecular responses in skeletal muscle and evidence for the interference effect with concurrent training within the context of the specificity of training adaptation.

10 weeks of heavy strength training improves performance-related measurements in elite cyclists

Elite cyclists have often a limited period of time available during their short preparation phase to focus on development of maximal strength; therefore, the purpose of the present study was to investigate the effect of 10-week heavy strength training on lean lower-body mass, leg strength, determinants of cycling performance and cycling performance in elite cyclists. Twelve cyclists performed heavy strength training and normal endurance training (E&S) while 8 other cyclists performed normal endurance training only (E). Following the intervention period E&S had a larger increase in maximal isometric half squat, mean power output during a 30-s Wingate sprint (P < 0.05) and a tendency towards larger improvement in power output at 4 mmol ∙ L^-1 [la^-] than E (P = 0.068). There were no significant difference between E&S and E in changes in 40-min all-out trial (4 ± 6% vs. -1 ± 6%, respectively, P = 0.13). These beneficial effects may encourage elite cyclists to perform heavy strength training and the short period of only 10 weeks should make it executable even in the compressed training and competition schedule of elite cyclists.

Effects of Heavy Strength Training on Running Performance and Determinants of Running Performance in Female Endurance Athletes

Purpose

The purpose of the current study was to investigate the effects of adding strength training to normal endurance training on running performance and running economy in well-trained female athletes. We hypothesized that the added strength training would improve performance and running economy through altered stiffness of the muscle-tendon complex of leg extensors.

Methods

Nineteen female endurance athletes [maximal oxygen consumption (VO_2max): 53±3 ml∙kg^-1∙min^-1, 5.8 h weekly endurance training] were randomly assigned to either normal endurance training (E, n = 8) or normal endurance training combined with strength training (E+S, n = 11). The strength training consisted of four leg exercises [3 x 4–10 repetition maximum (RM)], twice a week for 11 weeks. Muscle strength, 40 min all-out running distance, running performance determinants and patellar tendon stiffness were measured before and after the intervention.

Results

E+S increased 1RM in leg exercises (40 ± 15%) and maximal jumping height in counter movement jump (6 ± 6%) and squat jump (9 ± 7%, p < 0.05). This was accompanied by increased muscle fiber cross sectional area of both fiber type I (13 ± 7%) and fiber type II (31 ± 20%) in m. vastus lateralis (p < 0.05), with no change in capillary density in m. vastus lateralis or the stiffness of the patellar tendon. Neither E+S nor E changed running economy, fractional utilization of VO_2max or VO_2max. There were also no change in running distance during a 40 min all-out running test in neither of the groups.

Conclusion

Adding heavy strength training to endurance training did not affect 40 min all-out running performance or running economy compared to endurance training only.

Intensive training and reduced volume increases muscle FXYD1 expression and phosphorylation at rest and during exercise in athletes

The present study examined the effect of intensive training in combination with marked reduction in training volume on phospholemman (FXYD1) expression and phosphorylation at rest and during exercise. Eight well-trained cyclists replaced their regular training with speed-endurance training (10-12 × ∼30-s sprints) two or three times per week and aerobic high-intensity training (4-5 × 3-4 min at 90-95% of peak aerobic power output) 1-2 times per week for 7 wk and reduced the training volume by 70%. Muscle biopsies were obtained before and during a repeated high-intensity exercise protocol, and protein expression and phosphorylation were determined by Western blot analysis. Expression of FXYD1 (30%), actin (40%), mammalian target of rapamycin (mTOR) (12%), phospholamban (PLN) (16%), and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) γ/δ (25%) was higher (P < 0.05) than before the training intervention. In addition, after the intervention, nonspecific FXYD1 phosphorylation was higher (P < 0.05) at rest and during exercise, mainly achieved by an increased FXYD1 Ser-68 phosphorylation, compared with before the intervention. CaMKII, Thr-287, and eukaryotic elongation factor 2 Thr-56 phosphorylation at rest and during exercise, overall PKCα/β, Thr-638/641, and mTOR Ser-2448 phosphorylation during repeated intense exercise as well as resting PLN Thr-17 phosphorylation were also higher (P < 0.05) compared with before the intervention period. Thus, a period of high-intensity training with reduced training volume increases expression and phosphorylation levels of FXYD1, which may affect Na(+)/K(+) pump activity and muscle K(+) homeostasis during intense exercise. Furthermore, higher expression of CaMKII and PLN, as well as increased phosphorylation of CaMKII Thr-287 may have improved intracellular Ca(2+) handling.

Mechanisms underlying enhancements in muscle force and power output during maximal cycle ergometer exercise induced by chronic β2-adrenergic stimulation in men

The study was a randomized placebo-controlled trial investigating mechanisms by which chronic β2-adrenergic stimulation enhances muscle force and power output during maximal cycle ergometer exercise in young men. Eighteen trained men were assigned to an experimental group [oral terbutaline 5 mg/30 kg body weight (bw) twice daily (TER); n = 9] or a control group [placebo (PLA); n = 9] for a 4-wk intervention. No changes were observed with the intervention in PLA. Isometric muscle force of the quadriceps increased ( P ≤ 0.01) by 97 ± 29 N (means ± SE) with the intervention in TER compared with PLA. Peak and mean power output during 30 s of maximal cycling increased ( P ≤ 0.01) by 32 ± 8 and 25 ± 9 W, respectively, with the intervention in TER compared with PLA. Maximal oxygen consumption (V̇o2max) and time to fatigue during incremental cycling did not change with the intervention. Lean body mass increased by 1.95 ± 0.8 kg ( P ≤ 0.05) with the intervention in TER compared with PLA. Change in single fiber cross-sectional area of myosin heavy chain (MHC) I (1,205 ± 558 μm2; P ≤ 0.01) and MHC II fibers (1,277 ± 595 μm2; P ≤ 0.05) of the vastus lateralis muscle was higher for TER than PLA with the intervention, whereas no changes were observed in MHC isoform distribution. Expression of muscle proteins involved in growth, ion handling, lactate production, and clearance increased ( P ≤ 0.05) with the intervention in TER compared with PLA, with no change in oxidative enzymes. Our observations suggest that muscle hypertrophy is the primary mechanism underlying enhancements in muscle force and peak power during maximal cycling induced by chronic β2-adrenergic stimulation in humans.

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 VO2 max 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 VO2 max , 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.

A time-saving method to assess power output at lactate threshold in well-trained and elite cyclists

The purpose of this study was to examine the relationship between lactate threshold (LT) as a percentage of maximal oxygen consumption (V[Combining Dot Above]O2max) and power output at LT (LTW) and also to investigate to what extent V[Combining Dot Above]O2max, oxygen cost of cycling (CC), and maximal aerobic power (MAP) determine LTW in cycling to develop a new time-saving model for testing LTW. To do this, 108 male competitive cyclists with an average V[Combining Dot Above]O2max of 65.2 ± 7.4 ml·kg·min and an average LTW of 274 ± 43 W were tested for V[Combining Dot Above]O2max, LT %V[Combining Dot Above]O2max, LTW, MAP, and CC on a test ergometer cycle. The product of MAP and individual LT in %V[Combining Dot Above]O2max was found to be a good determinant of LTW (R = 0.98, p < 0.0001). However, LT in %V[Combining Dot Above]O2max was found to be a poor determinant of LTW (R = 0.39, p < 0.0001). Based on these findings, we have suggested a new time-saving method for calculating LTW in well-trained cyclists. The benefits from this model come both from tracking LTW during training interventions and from regularly assessing training status in competitive cyclists. Briefly, this method is based on the present findings that LTW depends on LT in %V[Combining Dot Above]O2max, V[Combining Dot Above]O2max, and CC and may after an initial test session reduce the time for the subsequent testing of LTW by as much as 50% without the need for blood samples.

Performance and neuromuscular adaptations following differing ratios of concurrent strength and endurance training

The interference effect attenuates strength and hypertrophic responses when strength and endurance training are conducted concurrently; however, the influence of training frequency on these responses remain unclear when varying ratios of concurrent strength and endurance training are performed. Therefore, the purpose of the study was to examine the strength, limb girth, and neuromuscular adaptations to varying ratios of concurrent strength and endurance training. Twenty-four men with >2 years resistance training experience completed 6 weeks of 3 days per week of (a) strength training (ST), (b) concurrent strength and endurance training ratio 3:1 (CT3), (c) concurrent strength and endurance training ratio 1:1 (CT1), or (d) no training (CON) in an isolated limb model. Assessments of maximal voluntary contraction by means of isokinetic dynamometry leg extensions (maximum voluntary suppression [MVC]), limb girth, and neuromuscular responses through electromyography (EMG) were conducted at baseline, mid-intervention, and postintervention. After training, ST and CT3 conditions elicited greater MVC increases than CT1 and CON conditions (p ≤ 0.05). Strength training resulted in significantly greater increases in limb girth than both CT1 and CON conditions (p = 0.05 and 0.004, respectively). The CT3 induced significantly greater limb girth adaptations than CON condition (p = 0.04). No effect of time or intervention was observed for EMG (p > 0.05). In conclusion, greater frequencies of endurance training performed increased the magnitude of the interference response on strength and limb girth responses after 6 weeks of 3 days a week of training. Therefore, the frequency of endurance training should remain low if the primary focus of the training intervention is strength and hypertrophy.

Strength training improves performance and pedaling characteristics in elite cyclists

The purpose was to investigate the effect of 25 weeks heavy strength training in young elite cyclists. Nine cyclists performed endurance training and heavy strength training (ES) while seven cyclists performed endurance training only (E). ES, but not E, resulted in increases in isometric half squat performance, lean lower body mass, peak power output during Wingate test, peak aerobic power output (W(max)), power output at 4 mmol L(-1)[la(-)], mean power output during 40-min all-out trial, and earlier occurrence of peak torque during the pedal stroke (P < 0.05). ES achieved superior improvements in W(max) and mean power output during 40-min all-out trial compared with E (P < 0.05). The improvement in 40-min all-out performance was associated with the change toward achieving peak torque earlier in the pedal stroke (r = 0.66, P < 0.01). Neither of the groups displayed alterations in VO2max or cycling economy. In conclusion, heavy strength training leads to improved cycling performance in elite cyclists as evidenced by a superior effect size of ES training vs E training on relative improvements in power output at 4 mmol L(-1)[la(-)], peak power output during 30-s Wingate test, W(max), and mean power output during 40-min all-out trial.

Anaerobic capacity of amateur mountain bikers during the first half of the competition season

Sustained aerobic exercise not only affects the rate of force development but also decreases peak power development. The aim of this study was to investigate whether anaerobic power of amateur mountain bikers changes during the first half of the competition season. Eight trained cyclists (mean ± SE: age: 22.0 ±0.5 years; height: 174.6 ± 0.9 cm; weight: 70.7 ± 2.6 kg) were subjected to an ergocycle incremental exercise test and to the Wingate test on two occasions: before, and in the middle of the season. After the incremental exercise test the excess post-exercise oxygen consumption was measured during 5-min recovery. Blood lactate concentration was measured in the 4th min after the Wingate test. Maximum oxygen uptake increased from 60.0 ± 1.5 ml min^-1 kg^-1 at the beginning of the season to 65.2 ± 1.4 ml min^-1 kg^-1 (P < 0.05) in the season. Neither of the mechanical variables of the Wingate test nor excess post-exercise oxygen consumption values were significantly different in these two measurements. However, blood lactate concentration was significantly higher (P < 0.001) in season (11.0 ± 0.5 mM) than before the season (8.6 ± 0.4 mM). It is concluded that: 1) despite the increase of cyclists’ maximum oxygen uptake during the competition season their anaerobic power did not change; 2) blood lactate concentration measured at the 4th min after the Wingate test does not properly reflect training-induced changes in energy metabolism.

Optimizing strength training for running and cycling endurance performance: A review

Here we report on the effect of combining endurance training with heavy or explosive strength training on endurance performance in endurance-trained runners and cyclists. Running economy is improved by performing combined endurance training with either heavy or explosive strength training. However, heavy strength training is recommended for improving cycling economy. Equivocal findings exist regarding the effects on power output or velocity at the lactate threshold. Concurrent endurance and heavy strength training can increase running speed and power output at VO2max (Vmax and Wmax, respectively) or time to exhaustion at Vmax and Wmax. Combining endurance training with either explosive or heavy strength training can improve running performance, while there is most compelling evidence of an additive effect on cycling performance when heavy strength training is used. It is suggested that the improved endurance performance may relate to delayed activation of less efficient type II fibers, improved neuromuscular efficiency, conversion of fast-twitch type IIX fibers into more fatigue-resistant type IIA fibers, or improved musculo-tendinous stiffness.

Anaerobic power in road cyclists is improved after 10 weeks of whole-body vibration training

Whole-body vibration (WBV) training has previously improved muscle power in various athletic groups requiring explosive muscle contractions. To evaluate the benefit of including WBV as a training adjunct for improving aerobic and anaerobic cycling performance, road cyclists (n = 9) performed 3 weekly, 10-minute sessions of intermittent WBV on synchronous vertical plates (30 Hz) while standing in a static posture. A control group of cyclists (n = 8) received no WBV training. Before and after the 10-week intervention period, lean body mass (LBM), cycling aerobic peak power (Wmax), 4 mM lactate concentration (OBLA), VO2peak, and Wingate anaerobic peak and mean power output were determined. The WBV group successfully completed all WBV sessions but reported a significant 30% decrease in the weekly cycling training time (pre: 9.4 ± 3.3 h·wk(-1); post: 6.7 ± 3.7 h·wk(-1); p = 0.01) that resulted in a 6% decrease in VO2peak and a 4% decrease in OBLA. The control group reported a nonsignificant 6% decrease in cycling training volume (pre: 9.5 ± 3.6 h·wk(-1); 8.6 ± 2.9 h·wk(-1); p = 0.13), and all measured variables were maintained. Despite the evidence of detraining in the WBV group, Wmax was maintained (pre: 258 ± 53 W; post: 254 ± 57 W; p = 0.43). Furthermore, Wingate peak power increased by 6% (668 ± 189 to 708 ± 220 W; p = 0.055), and Wingate mean power increased by 2% (553 ± 157 to 565 ± 157 W; p = 0.006) in the WBV group from preintervention to postintervention, respectively, without any change to LBM. The WBV training is an attractive training supplement for improving anaerobic power without increasing muscle mass in road cyclists.

Sex differences in time to fatigue at 100% VO2 peak when normalized for fat free mass

The purpose of this investigation was to compare sexes for time to fatigue at 100% VO(2)peak in recreationally trained individuals. Ten men (age: 23.4 ± 1.8; height: 177 ± 6.7; body mass: 83.8 ± 11.3; ± SD) and nine women (age: 25.0 ± 2.5; height: 165.6 ± 5.5; body mass: 62.7 ± 6.7) participated in this investigation after providing written consent. One week after assessing VO(2)peak, subjects exercised on an electrically braked cycle ergometer at 100% of VO(2)peak until fatigue. The time taken to fatigue was 48.9% longer for men than women (274 ± 13s vs. 184 ± 14s; p < 0.001, for men and women, respectively). When normalized for fat free mass (ffm; s/kg ffm) no significant differences between men and women were observed (3.99 ± 0.21s/kg ffm vs. 3.72 ± 0.28s/kg ffm for men and women, respectively, p = 0.431). The difference in fatigability between the sexes at this exercise intensity is to a large degree related to the difference in fat free mass.

Cyclists’ Improvement of Pedaling Efficacy and Performance After Heavy Strength Training

The authors tested whether heavy strength training, including hip-flexion exercise, would reduce the extent of the phase in the crank revolution where negative or retarding crank torque occurs. Negative torque normally occurs in the upstroke phase when the leg is lifted by flexing the hip. Eighteen well-trained cyclists either performed 12 wk of heavy strength training in addition to their usual endurance training (E+S; n = 10) or merely continued their usual endurance training during the intervention period (E; n = 8). The strength training consisted of 4 lower body exercises (3 × 4–10 repetition maximum) performed twice a week. E+S enhanced cycling performance by 7%, which was more than in E (P = .02). Performance was determined as average power output in a 5-min all-out trial performed subsequent to 185 min of submaximal cycling. The performance enhancement, which has been reported previously, was here shown to be accompanied by improved pedaling efficacy during the all-out cycling. Thus, E+S shortened the phase where negative crank torque occurs by ~16°, corresponding to ~14%, which was more than in E (P = .002). In conclusion, adding heavy strength training to usual endurance training in well-trained cyclists improves pedaling efficacy during 5-min all-out cycling performed after 185 min of cycling.

Performance analysis of a world-class sprinter during cycling grand tours

This investigation describes the sprint performances of the highest internationally ranked professional male road sprint cyclist during the 2008-2011 Grand Tours. Sprint stages were classified as won, lost, or dropped from the front bunch before the sprint. Thirty-one stages were video-analyzed for average speed of the last km, sprint duration, position in the bunch, and number of teammates at 60, 30, and 15 s remaining. Race distance, total elevation gain (TEG), and average speed of 45 stages were determined. Head-to-head performances against the 2nd-5th most successful professional sprint cyclists were also reviewed. In the 52 Grand Tour sprint stages the subject started, he won 30 (58%), lost 15 (29%), was dropped in 6 (12%), and had 1 crash. Position in the bunch was closer to the front and the number of team members was significantly higher in won than in lost at 60, 30, and 15 s remaining (P < .05). The sprint duration was not different between won and lost (11.3 ± 1.7 and 10.4 ± 3.2 s). TEG was significantly higher in dropped (1089 ± 465 m) than in won and lost (574 ± 394 and 601 ± 423 m, P < .05). The ability to finish the race with the front bunch was lower (77%) than that of other successful sprinters (89%). However, the subject was highly successful, winning over 60% of contested stages, while his competitors won less than 15%. This investigation explores methodology that can be used to describe important aspects of road sprint cycling and supports the concept that tactical aspects of sprinting can relate to performance outcomes.

Improved cycling performance with ingestion of hydrolyzed marine protein depends on performance level

Background

The effect on performance of protein ingestion during or after exercise is not clear. This has largely been attributed to the utilization of different scientific protocols and the neglection of accounting for factors such as differences in physical and chemical properties of protein supplements and differences in athletic performance level.

Methods

We hypothesized that ingestion of unprocessed whey protein (15.3 g·h^-1) together with carbohydrate (60 g·h^-1), would provide no ergogenic effect on 5-min mean-power performance following 120 min cycling at 50% of maximal aerobic power (2.8 ± 0.2 W·kg^-1, corresponding to 60 ± 4% of VO_2max), compared to CHO alone (60 g·h^-1). Conversely, we hypothesized that ingestion of the hydrolyzed marine protein supplement NutriPeptin™ (Np, 2.7 g·h^-1), a processed protein supplement with potentially beneficial amino acid composition, together with a PROCHO beverage (12.4 g·h^-1 and 60 g·h^-1, respectively) would provide an ergogenic effect on mean-power performance. We also hypothesized that the magnitude of the ergogenic effect of NpPROCHO would be dependent on athletic performance. As for the latter analysis, performance level was defined according to a performance factor, calculated from individual pre values of W_max, VO_2max and 5-min mean-power performance, wherein the performance of each subject was ranked relative to the superior cyclist whos performance was set to one. Twelve trained male cyclists (VO_2max = 65 ± 4 ml·kg^-1·min^-1) participated in a randomized double-blinded cross-over study.

Results and conclusions

Overall, no differences were found in 5-min mean-power performance between either of the beverages (CHO 5.4 ± 0.5 W·kg^-1; PROCHO 5.3 ± 0.5 W·kg^-1; NpPROCHO 5.4 ± 0.3 W·kg^-1) (P = 0.29). A negative correlation was found between NpPROCHO mean-power performance and athletic performance level (using CHO-performance as reference; Pearson R = -0.74, P = 0.006). Moreover, ingestion of NpPROCHO resulted in improved 5-min mean-power performance relative to ingestion of CHO in the six lesser performing subjects compared to the six superior performing subjects (P < 0.05). This suggests that with the current protocol, NpPROCHO provided an ergogenic effect on 5-min mean-power performance in athletes with a lower performance level.

Effect of heavy strength training on muscle thickness, strength, jump performance, and endurance performance in well-trained Nordic Combined athletes

The purpose of the present study was to investigate the effect of supplemental heavy strength training on muscle thickness and determinants of performance in well-trained Nordic Combined athletes. Seventeen well-trained Nordic Combined athletes were assigned to either usual training supplemented with heavy strength training (STR; n = 8) or to usual training without heavy strength training (CON; n = 9). The strength training performed by STR consisted of one lower-body exercise and two upper-body exercises [3-5 repetition maximum (RM) sets of 3-8 repetitions], which were performed twice a week for 12 weeks. Architectural changes in m. vastus lateralis, 1RM in squat and seated pull-down, squat jump (SJ) height, maximal oxygen consumption (VO(2max)), work economy during submaximal treadmill skate rollerskiing, and performance in a 7.5-km rollerski time trial were measured before and after the intervention. STR increased 1RM in squat and seated pull-down, muscle thickness, and SJ performance more than CON (p < 0.05). There was no difference between groups in change in work economy. The two groups showed no changes in total body mass, VO(2max), or time-trial performance. In conclusion, 12 weeks of supplemental strength training improved determinants of performance in Nordic Combined by improving the athletes' strength and vertical jump ability without increasing total body mass or compromising the development of VO(2max).

High volume of endurance training impairs adaptations to 12 weeks of strength training in well-trained endurance athletes

The purpose of the present study was to compare the effect of 12 weeks of strength training combined with a large volume of endurance training with the effect of strength training alone on the strength training adaptations. Well-trained cyclists with no strength training experience performed heavy strength training twice a week in addition to a high volume of endurance training during a 12-week preparatory period (S + E; n = 11). A group of non-strength trained individuals performed the same strength training as S + E, but without added endurance training (S; n = 7). Thigh muscle cross-sectional area, 1 repetition maximum (1RM) in leg exercises, squat jump performance, and peak rate of force development (RFD) were measured. Following the intervention period, both S + E and S increased 1RM strength, thigh muscle cross-sectional area, and squat jump performance (p < 0.05), and the relative improvements in S were greater than in S + E (p < 0.05). S increased peak RFD while S + E did not, and this improvement was greater than in S + E (p < 0.05). To the best of our knowledge, this is the first controlled study to demonstrate that the strength training response on muscle hypertrophy, 1RM strength, squat jump performance, and peak RFD is attenuated in well-trained endurance athletes during a period of concurrent endurance training.

Effects of strength, endurance, and concurrent training on aerobic power and dynamic neuromuscular economy in elderly men

The aim of this study was to investigate the effects of concurrent training on endurance capacity and dynamic neuromuscular economy in elderly men. Twenty-three healthy men (65 ± 4 years) were divided into 3 groups: concurrent (CG, n = 8), strength (SG, n = 8), and aerobic training group (EG, n = 7). Each group trained 3 times a week for 12 weeks, strength training, aerobic training, or both types of training in the same session. The maximum aerobic workload (Wmax) and peak oxygen uptake (VO2peak) of the subjects were evaluated on a cycle ergometer before and after the training period. Moreover, during the maximal test, muscle activation was measured at each intensity by means of electromyographic signals from the vastus lateralis (VL), rectus femoris (RF), biceps femoris long head, and gastrocnemius lateralis to determine the dynamic neuromuscular economy. After training, significant increases in VO2peak and Wmax were only found in the CG and EG (p < 0.05), with no difference between groups. Moreover, there was a significant decrease in myoelectric activity of the RF muscle at 50 (EG), 75 and 100 W (EG and CG) and in the VL for the 3 groups at 100 W (p < 0.05). No change was seen in the electrical signal from the lateral gastrocnemius muscle and biceps femoris. The results suggest specificity in adaptations investigated in elderly subjects, because the most marked changes in the neuromuscular economy occurred in the aerobically trained groups.

Strategies to optimize concurrent training of strength and aerobic fitness for rowing and canoeing

During the last several decades many researchers have reported an interference effect on muscle strength development when strength and endurance were trained concurrently. The majority of these studies found that the magnitude of increase in maximum strength was higher in the group that performed only strength training compared with the concurrent training group, commonly referred to as the 'interference phenomenon'. Currently, concurrent strength and endurance training has become essential to optimizing athletic performance in middle- and long-distance events. Rowing and canoeing, especially in the case of Olympic events, with exercise efforts between 30 seconds and 8 minutes, require high amounts of maximal aerobic and anaerobic capacities as well as high levels of maximum strength and muscle power. Thus, strength training, in events such as rowing and canoeing, is integrated into the training plan. However, several studies indicate that the degree of interference is affected by the training protocols and there may be ways in which the interference effect can be minimized or avoided. Therefore, the aim of this review is to recommend strategies, based on research, to avoid or minimize any interference effect when training to optimize performance in endurance sports such as rowing and canoeing.

In-season strength maintenance training increases well-trained cyclists' performance

We investigated the effects of strength maintenance training on thigh muscle cross-sectional area (CSA), leg strength, determinants of cycling performance, and cycling performance. Well-trained cyclists completed either (1) usual endurance training supplemented with heavy strength training twice a week during a 12-week preparatory period followed by strength maintenance training once a week during the first 13 weeks of a competition period (E + S; n = 6 [♂ = 6]), or (2) usual endurance training during the whole intervention period (E; n = 6 [♂ = 5, ♀ = 1]). Following the preparatory period, E + S increased thigh muscle CSA and 1RM (p < 0.05), while no changes were observed in E. Both groups increased maximal oxygen consumption and mean power output in the 40-min all-out trial (p < 0.05). At 13 weeks into the competition period, E + S had preserved the increase in CSA and strength from the preparatory period. From the beginning of the preparatory period to 13 weeks into the competition period, E + S increased peak power output in the Wingate test, power output at 2 mmol l(-1) [la(-)], maximal aerobic power output (W (max)), and mean power output in the 40-min all-out trial (p < 0.05). The relative improvements in the last two measurements were larger than in E (p < 0.05). For E, W (max) and power output at 2 mmol l(-1) [la(-)] remained unchanged. In conclusion, in well-trained cyclists, strength maintenance training in a competition period preserved increases in thigh muscle CSA and leg strength attained in a preceding preparatory period and further improved cycling performance determinants and performance.