High-intensity Cycling Training Research Articles

High-Intensity Cycling Training Necessitates Increased Neuromuscular Demand of the Vastus Lateralis During a Fatiguing Contraction

ABSTRACT Purpose: To examine the effects of a 5-week continuous cycling training intervention on electromyographic amplitude (EMGRMS)- and mechanomyographic amplitude (MMGRMS)-torque relationships of the vastus lateralis (VL) during a prolonged contraction. Methods: Twenty-four sedentary, young adults performed maximal voluntary contractions (MVCs) and a prolonged isometric trapezoidal contraction at the same absolute 40% MVC for the knee extensors before (PRE) and after training (POSTABS). Individual b- (slopes) and a-terms (y-intercepts) were calculated from the log-transformed electromyographic amplitude (EMGRMS)- and mechanomyographic amplitude (MMGRMS)-torque relationships during the increasing and decreasing segments of the trapezoid. EMGRMS and MMGRMS was normalized for the 45-s steady torque segment. Results: At PRE, b-terms for the EMGRMS-torque relationships during the linearly decreasing segment were greater than the increasing segment (p < .001), and decreased from PRE to POSTABS (p = .027). a-terms were greater during the linearly increasing than decreasing segment at PRE, while the a-terms for the linearly decreasing segment increased from PRE to POSTABS (p = .027). For the MMGRMS-torque relationships, b-terms during the linearly decreasing segment decreased from PRE to POSTABS (p = .013), while a-terms increased from PRE to POSTABS when collapsed across segments (p = .022). Steady torque EMGRMS increased for POSTABS (p < .001). Conclusion: Although cycling training increased aerobic endurance, incorporating resistance training may benefit athletes/individuals as the alterations in neuromuscular parameters post-training suggest a greater neural cost (EMGRMS) and mechanical output (MMGRMS) to complete the same pre-training fatiguing contraction.

The ergogenic effect of acute carnosine and anserine supplementation: dosing, timing, and underlying mechanism.

ABSTRACTBackgroundRecent studies suggest that acute-combined carnosine and anserine supplementation has the potential to improve the performance of certain cycling protocols. Yet, data on optimal dose, timing of ingestion, effective exercise range, and mode of action are lacking. Three studies were conducted to establish dosing and timing guidelines concerning carnosine and anserine intake and to unravel the mechanism underlying the ergogenic effects.MethodsFirst, a dose response study A was conducted in which 11 men randomly received placebo, 10, 20, or 30 mg.kg−1 of both carnosine and anserine. They performed 3x maximal voluntary isometric contractions (MVC), followed by a 5 x 6 s repeated cycling sprint ability test (RSA), once before the supplement and 30 and 60 minutes after. In a second study, 15 men performed 3x MVCs with femoral nerve electrical stimulation, followed by an RSA test, once before 30 mg.kg−1 carnosine and anserine and 60 minutes after. Finally, in study C, eight men performed a high intensity cycling training after randomly ingesting 30 mg.kg−1 of carnosine and anserine, a placebo or antihistamines (reduce post-exercise blood flow) to investigate effects on muscle perfusion.ResultsStudy A showed a 3% peak power (p = 0.0005; 95% CI = 0.07 to 0.27; ES = 0.91) and 4.5% peak torque (p = 0.0006; 95% CI = 0.12 to 0.50; ES = 0.87) improvement on RSA and MVC, with 30 mg.kg−1 carnosine + anserine ingestion 60 minutes before the performance yielding the best results. Study B found no performance improvement on group level; however, a negative correlation (r = −0.54; p = 0.0053; 95% CI = −0.77 to −0.19) was found between carnosinase enzyme activity (responsible for carnosine and anserine breakdown) and performance improvement. No effect of the supplement on neuromuscular function nor on muscle perfusion was found.ConclusionsThese studies reveal that acute ingestion of 30 mg.kg−1 of both carnosine and anserine, 60 minutes before a high intensity exercise, can potentially improve performance, such as short cycling sprints or maximal muscle contractions. Subjects with lower carnosinase activity, and thus a slower breakdown of circulating dipeptides, appear to benefit more from this ergogenic effect. Finally, neither the involvement of a direct effect on neuromuscular function, nor an indirect effect on recovery through increased muscle perfusion could be confirmed as potential mechanism of action. The ergogenic mechanism therefore remains elusive.

Effect of a high-intensity short-duration cycling elevation training mask on V̇O2max and anaerobic power. A randomized controlled trial.

This study investigated the effect of high-intensity interval training (HIIT) cycling elevation training mask (ETM) in moderately trained participants on both aerobic (V̇O2max) and anaerobic power performance. Sixteen participants, five females (25.8 ± 7.6 years) and eleven males (22.2 ± 3.5 years) took part in this randomized controlled trial. Participants were assigned to the experimental group (ETM, n = 8 participants) wearing an ETM or the control group (CON, n = 8 participants) without the ETM. V̇O2max was determined during a standardized protocol using Cortex Metalyzer-3B on a cycle ergometer. Peak and average power were calculated a 30-second Wingate test. Participants completed 4-weeks (two sessions a week) of high-intensity cycle training. Each training session consisting of 4 separate bouts of 4-minutes of high-intensity cycling exercise. After the training period, ETM reported an increment in V̇O2max (effect size (d) = 1.19), peak power (d = 0.77), and average power (d = 0.76). CON reported an increment only in V̇O2max (d = 1.00). No-between group differences were found in any parameter (ANCOVA), therefore the two protocols should be considered equally effective. In conclusion, this study reported that both HIIT protocols significantly enhance V̇O2max in a very short training period (4 weeks).

Six weeks of high intensity cycle training reduces H2O2 emission and increases antioxidant protein levels in obese adults with risk factors for type 2 diabetes

Obesity has been associated with increased production of reactive oxygen species (ROS), which may be involved in the development of cardiovascular disease and type 2 diabetes (T2D). Endurance exercise lowers ROS production and increases antioxidant capacity in muscle cells, but it is currently unknown whether high intensity interval training (HIT) elicits the same effects. Twelve sedentary obese subjects at risk of developing T2D took part in a six-week intervention, performing three HIT sessions per week (five 1-min sets of high-intensity cycling (125% of VO2peak), with 90 s recovery in between sets). Muscle biopsies were obtained for assessment of ROS production (H2O2 emission), mitochondrial respiratory capacity, and antioxidant protein levels before and after the intervention. H2O2 emission decreased 60.4% after the intervention (Succinate 3 mmol･l−1), concurrent with a 35.1% increase in protein levels of the antioxidant manganese superoxide dismutase (MnSOD) and a trend towards increased levels of the antioxidant catalase (p = 0.06, 72.9%). These findings were accompanied by a 19% increased mitochondrial respiratory capacity (CI + II), a 6.9% increased VO2peak and a 1.7% lower body fat percentage. These effects were achieved after just 15 min of high-intensity work and 40 min of total time spent per week. Overall, this suggests that a relatively small amount of HIT is sufficient to induce beneficial effects on ROS production and antioxidant status in muscle cells, which may lower oxidative stress and potentially protect against the development of cardiovascular disease.

Aerobic High-Intensity Exercise Training Improves Cardiovascular Health in Older Post-menopausal Women.

The aim of this study was to determine the effect of a period of aerobic high intensity training on central- and peripheral cardiovascular parameters in older post-menopausal women. Eleven healthy post-menopausal (>10 years after menopause) women (mean age: 64 years; BMI: 25.3 kg m−2) completed an 8-week period of supervised, high intensity cycle training, with sessions conducted three times per week. Before and after the training period maximal oxygen uptake, body composition, popliteal artery flow mediated dilation, exercise hyperemia, arterial blood pressure, and plasma lipids were assessed. In addition, levels of estrogen related receptor α (ERRα) and vasodilator enzymes were determined in muscle biopsy samples. Training induced an 18% increase (P < 0.001) in maximal oxygen uptake. Plasma High-density lipoprotein (HDL) was higher (P < 0.05) after than before the training period. Fat mass was reduced (4.9%; P < 0.01), whereas lean body mass was unaltered. Mean arterial blood pressure was unchanged (91 vs. 88 mmHg; P = 0.058) with training. Training did not induce a change in popliteal flow mediated dilation. Exercise hyperemia at submaximal exercise was lower (P < 0.01; 11 and 4.6% at 10 and 16 W, respectively) after compared to before training. Muscle ERRα (~1.7-fold; P < 0.01) and eNOS (~1.4-fold; P < 0.05) were higher after the training intervention. The current study demonstrates that, in older post-menopausal women, a period of aerobic high intensity training effectively increases maximal oxygen uptake and improves the cardiovascular health profile, without a parallel improvement in conduit artery function.

Cycling-based repeat sprint training in the heat enhances running performance in team sport players

Applying heat training interventions in a team sports setting remains challenging. This study investigated the effects of integrating short-term, repeat sprint heat training with passive heat exposure on running performance and general conditioning in team sport players. Thirty male club-level Australian Football players were assigned randomly to: Passive + Active Heat (PAH; n = 10), Active Heat (AH; n = 10) or Control (CON; n = 10) to complete 6 × 40 min high-intensity cycling training sessions over 12 days in 35°C (PAH and AH) or 18°C (CON), 50% RH in parallel with mid-season sports-specific training and games. Players in PAH were exposed to 20 min pre-exercise passive heat. Physiological adaptation and running capacity were assessed via a treadmill submaximal heat stress test followed by a time-to-exhaustion run in 35°C, 50% RH. Running capacity increased by 26% ± 8% PAH (0.88, ±0.23; standardised mean, ± 90% confidence limits), 29% ± 12% AH (1.23, ±0.45) and 10% ± 11% CON (0.45, ±0.48) compared with baseline. Both PAH (0.52, ±0.42; standardised mean, ± 90% confidence limits) and AH (0.35, ±0.57) conditions yielded a greater improvement in running capacity than CON. Physiological and perceptual measures remained relatively unchanged between baseline and post-intervention heat stress tests, within and between conditions. When thermal adaptation is not a direct priority, short-term, repeat effort high-intensity cycling in hot conditions combined with sports-specific training can further enhance running performance in team sport players. Six heat exposures across 12-days should improve running performance while minimising lower limb load and cumulative fatigue for team sports players.

Transferable Benefits of Cycle Hypoventilation Training for Run-Based Performance in Team-Sport Athletes.

To determine whether high-intensity training with voluntary hypoventilation at low lung volume (VHL) in cycling could improve running performance in team-sport athletes. Twenty well-fit subjects competing in different team sports completed, over a 3-week period, 6 high-intensity training sessions in cycling (repeated 8-s exercise bouts at 150% of maximal aerobic power) either with VHL or with normal breathing conditions. Before (Pre) and after (Post) training, the subjects performed a repeated-sprint-ability test (RSA) in running (12 × 20-m all-out sprints), a 200-m maximal run, and the Yo-Yo Intermittent Recovery Level 1 test (YYIR1). There was no difference between Pre and Post in the mean and best velocities reached in the RSA test, as well as in performance and maximal blood lactate concentration in the 200-m-run trial in both groups. On the other hand, performance was greater in the second part of the RSA test, and the fatigue index of this test was lower (5.18% [1.3%] vs 7.72% [1.6%]; P < .01) after the VHL intervention only. Performance was also greater in the YYIR1 in the VHL group (1468 [313] vs 1111 [248]m; P < .01), whereas no change occurred in the normal-breathing-condition group. This study showed that performing high-intensity cycle training with VHL could improve RSA and possibly endurance performance in running. On the other hand, this kind of approach does not seem to induce transferable benefits for anaerobic performance.

Evidence of a limb- and shear stress stimulus profile-dependent impact of high-intensity cycling training on flow-mediated dilation.

Lower limb endurance training can improve conduit artery flow-mediated dilation (FMD) in response to transient increases in shear stress (reactive hyperemia; RH-FMD) in both the upper and lower limbs. Sustained increases in shear stress recruit a partially distinct transduction pathway and elicit a physiologically relevant FMD response (SS-FMD) that provides distinct information regarding endothelial function. However, the impact of training on SS-FMD is not well understood. The purpose of this study was to determine the impact of cycling training on handgrip exercise-induced brachial artery (BA) FMD (BA SS-FMD) and calf plantar-flexion-induced superficial femoral artery (SFA) FMD (SFA SS-FMD). RH-FMD was also assessed in both arteries. Twenty-eight young males were randomized to control (n = 12) or training (n = 16) groups. The training group cycled 30 min/day, 3 days/week for 4 weeks at 80% heart rate reserve. FMD was assessed in the BA and SFA before and after the intervention via Duplex ultrasound. Results are means ± SD. Training did not impact SS-FMD in either artery, and SFA RH-FMD was also unchanged (p > 0.05). When controlling for the shear rate stimulus via covariate analysis, BA RH-FMD improved in the training group (p = 0.05) (control - pre-intervention: 5.7% ± 2.4%, post-intervention: 5.3% ± 2.4%; training - pre-intervention: 5.4% ± 2.5%, post-intervention: 7.2% ± 2.4%). Thus, endurance training resulted in nonuniform adaptations to endothelial function, with an isolated impact on the BA's ability to transduce a transient increase in shear stress. Novelty Training did not alter SS-FMD in the arm or leg. RH-FMD was augmented in the arm only. Thus training adaptations were limb- and shear stress profile-specific.

Effects of brisk walking on autonomic nervous system reactivation in nursing home residents. Additional effects of transcutaneous vagus nerve stimulation

It is well established that physical activity reduces the physiological effects of ageing. Among them, is the decrease of the autonomic nervous system (ANS) activity, which is associated with the increase of cardiovascular events and morbidities. It has been shown that high intensity cycle training can enhance the ANS activity by 30% in people with the age of 70. However, such trainings were done by old athletes, used to train at intensities that could not be tolerated by sedentary old people, such as nursing home residents. Furthermore, vagus nerve stimulation (VNS) is a novel technique that could potentialize the training effects on the ANS by reducing the parasympathetic activity decrease that occurs after an exhausting exercise. Therefore, we aim to compare the effects of a 9-month brisk walking training (1 time a week or 3 times a week) on the ANS of nursing home residents. Also, we wish to measure the effects of post exercise VNS stimulation on the ANS activity. One hundred and fifty 60-year-old subjects and older will be recruited within the ten nursing homes of La Mutualité française de la Loire, France, and will be randomized into 5 groups: – G1: one brisk walking session a week; – G2: one brisk walking session a week + VNS; – G3: three brisk walking sessions a week; – G4: three brisk walking sessions a week + VNS; – G5: control group (no training or VNS). Testing procedure will occur at the inclusion and after 3 months, 6 months and 9 months of training. The primary outcome measure is the heart rate variability (SDNN value) measured by 24 hours Holter ECG and baroreflex. We expect an increase of the ANS activity, particularly of the parasympathetic arm, with a dose–response relationship through training. The increase would be higher for the group of subjects having trained 3 times per week and who will receive VNS. Expected conclusion brisk walking training could enhance the ANS tone and could improve the parasympathetic/sympathetic balance in nursing home elderly. This effect would be potentialized by VNS.

The effect of high-intensity cycling training on postural sway during standing under rested and fatigued conditions in healthy young adults.

The purpose of this study was to investigate whether high-intensity cycling training leads to adapted responses of balance performance in response to exercise-induced muscle fatigue. Eighteen healthy adults were assigned to either 3-weeks (n=8, age 20.1±2.6years, height 177±5cm, mass 73.6±5.1kg) or 6-weeks (n=10, age 24.3±5.8years, height 179±6cm, mass 81.0±15.8kg) of high-intensity training (HIT) on a cycle ergometer. The centre of pressure (COP) displacement in the anteroposterior (COPAP) direction and COP path length (COPL) were measured before and after the first and final high-intensity training sessions. Pre-training, exercise-induced fatigue elicited an increase in COPAP (3-weeks; p=0.001, 6-weeks; p=0.001) and COPL (3-weeks; p=0.002, 6-weeks; p=0.001) returning to pre-exercise levels within 10-min of recovery. Following 3-weeks of training, significant increases in COPAP (p=0.001) and COPL (p=0.002) were observed post-fatigue, returning to pre-exercise levels after 15-min of recovery. After 6-weeks of training no significant increases in sway (COPAP; p=0.212, COPL; p=0.998) were observed following exercise-induced fatigue. In summary, 3weeks of HIT resulted in longer recovery times following fatigue compared to pre-training assessments. After 6weeks of HIT, postural sway following fatigue was attenuated. These results indicate that HIT could be included in injury prevention programmes, however, caution should be taken during early stages of the overreaching process.

High-Intensity Cycling Training: The Effect of Work-to-Rest Intervals on Running Performance Measures.

The work-to-rest ratio during cycling-based high-intensity interval training (HIT) could be important in regulating physiological and performance adaptations. We sought to determine the effectiveness of cycling-based HIT with different work-to-rest ratios for long-distance running. Thirty-two long-distance runners (age: 39 ± 8 years; sex: 14 men, 18 women; average weekly running training volume: 25 miles) underwent baseline testing (3-km time-trial, V[Combining Dot Above]O2peak and time to exhaustion, and Wingate test) before a 2-week matched-work cycling HIT of 6 × 10-second sprints with different rest periods (30 seconds [R30], 80 seconds [R80], 120 seconds [R120], or control). Three-kilometer time trial was significantly improved in the R30 group only (3.1 ± 4.0%, p = 0.04), whereas time to exhaustion was significantly increased in the 2 groups with a lower work-to-rest ratio (R30 group 6.4 ± 6.3%, p = 0.003 vs. R80 group 4.4 ± 2.7%, p = 0.03 vs. R120 group 1.9 ± 5.0%, p = 0.2). However, improvements in average power production were significantly greater with a higher work-to-rest ratio (R30 group 0.3 ± 4.1%, p = 0.8 vs. R80 group 4.6 ± 4.2%, p = 0.03 vs. R120 group 5.3 ± 5.9%, p = 0.02), whereas peak power significantly increased only in the R80 group (8.5 ± 8.2%, p = 0.04) but not in the R30 group (4.3 ± 6.1%, p = 0.3) or in the R120 group (7.1 ± 7.9%, p = 0.09). Therefore, cycling-based HIT is an effective way to improve running performance, and the type and magnitude of adaptation is dependent on the work-to-rest ratio.

Does six-weeks of high-intensity cycle training with induced changes in acid-base balance lead to mitochondrial adaptations?

Does six-weeks of high-intensity cycle training with induced changes in acid-base balance lead to mitochondrial adaptations?

Sprint interval running increases insulin sensitivity in young healthy subjects

High intensity cycling training increases oxidative capacity in skeletal muscles and improves insulin sensitivity. The present study compared the effect of eight weeks of sprint interval running (SIT) and continuous running at moderate intensity (CT) on insulin sensitivity and cholesterol profile in young healthy subjects (age 25.2 ± 0.7; VO2max 49.3 ± 1.2 ml·kg−1·min−1). SIT and CT increased maximal oxygen uptake by 5.3 ± 1.8 and 3.8 ± 1.6%, respectively (p < 0.05 for both). Oral glucose tolerance test (OGTT) was performed before and 60 h after the last training session. SIT, but not CT, reduced glucose area under curve and improved HOMA β-cell index (p < 0.05). Insulin area under curve did not decrease significantly in any group. SIT, but not CT, reduced LDL and total cholesterol. In conclusion, sprint interval running improves insulin sensitivity and cholesterol profile in healthy subjects, and sprint interval running may be more effective to improve insulin sensitivity than continuous running at moderate intensity.

Effect of pulmonary rehabilitation on muscle remodelling in cachectic patients with COPD

It is known that non-cachectic patients with chronic obstructive pulmonary disease (COPD) respond well to pulmonary rehabilitation, but whether cachectic COPD patients are capable of adaptive responses is both important and unknown. 10 cachectic and 19 non-cachectic COPD patients undertook high-intensity cycling training, at the same relative intensity, for 45 min x day(-1), 3 days x week(-1) for 10 weeks. Before and after rehabilitation vastus lateralis muscle biopsies were analysed morphologically and for the expression of muscle remodelling factors (insulin-like growth factor (IGF)-I, myogenic differentiation factor D (MyoD), tumour necrosis factor (TNF)-alpha, nuclear factor (NF)-kappaB and myostatin) and key components of ubiquitin-mediated proteolytic systems (muscle ring finger protein (MURF)-1 and Atrogin-1). Rehabilitation improved peak work-rate and the 6-min walk distance similarly in non-cachectic (18+/-3% and 42+/-13 m, respectively) and cachectic (16+/-2% and 53+/-16 m, respectively) patients, but quality of life only improved in non-cachectic COPD. Mean muscle fibre cross-sectional area increased in both groups, but significantly less in cachectic (7+/-2%) than in non-cachectic (11+/-2%) patients. Both groups equally decreased the proportion of type IIb fibres and increased muscle capillary/fibre ratio. IGF-I mRNA expression increased in both groups, but IGF-I protein levels increased more in non-cachectic COPD. MyoD was upregulated, whereas myostatin was downregulated at the mRNA and protein level only in non-cachectic patients. Whilst rehabilitation had no effect on TNF-alpha expression, it decreased the activation of the transcription factor NF-kappaB in both groups by the same amount. Atrogin-1 and MURF-1 expression were increased in cachectic COPD, but it was decreased in non-cachectic patients. Cachectic COPD patients partially retain the capacity for peripheral muscle remodelling in response to rehabilitation and are able to increase exercise capacity as much as those without cachexia, even if they exhibit both quantitative and qualitative differences in the type of muscle fibre remodelling in response to exercise training.

BMD Decreases Over the Course of a Year in Competitive Male Cyclists

Male cyclists have been found to have low BMD in cross-sectional studies. Changes in BMD values over 1 yr of training and competition were studied in 14 male cyclists. BMD decreased significantly at the total hip, neck, trochanter, and shaft regions but not the lumbar spine. This first prospective study of cyclists showed a decrease in BMD over the course of 1 yr. Cross-sectional studies have shown that some endurance athletes, and cyclists in particular, have low BMD. Whether vigorous cycle training is causally related with low BMD remains unknown. Changes in BMD values over 1 yr of training and competition were studied in 14 male road cyclists, 27-44 yr of age. Subjects were randomized to receive 1500 (500 mg with meals) or 250 mg of supplemental calcium citrate daily. BMD measurements were obtained at pre-, mid-, post-, and off-season time points over 1 yr. Dermal calcium loss during exercise was estimated using a patch collection technique to examine calcium loss as a potential mediator of changes in BMD. Using paired t-tests, BMD was found to decrease significantly from pre- to off-season at the total hip, neck, shaft, and trochanter regions (relative changes of -1.5 +/- 2.1%, -0.7 +/- 2.1%, -0.9 +/- 2.1%, and -1.0 +/- 1.2%, respectively, all p < 0.05). The 1.0 +/- 1.2% decrease in BMD at the lumbar spine failed to reach statistical significance (p = 0.079). There were no differences in changes in BMD between the calcium supplementation groups. The 2-h dermal calcium loss was estimated at 136.5 +/- 60.5 mg. Higher dermal calcium losses were associated with lower baseline BMD values at the total hip, neck, and shaft (all p < 0.05), but were not significantly associated with changes in BMD. This study suggests that high intensity cycle training may adversely affect BMD. Excessive dermal calcium loss during exercise may be a contributing factor, but mechanisms remain to be elucidated.

Altitude Tents Do Not Impair Performance Response To Short-term High-intensity Cycling Training

Sleep quality may be compromised at moderate altitude. It is therefore possible that use of altitude tents during periods of rigorous training may impair recovery and adaptation. Conversely, sleeping in an enriched oxygen environment may aid recovery and adaptation during successive days of intense training. PURPOSE To examine whether sleeping at simulated altitude during seven days of race-specific high-intensity cycling training interferes with cycling performance. METHODS: Seven regionally competitive male cyclists (19±1 yr; 72.4±11.7 kg; 4.73±0.66 L·min−1 VO2pk) completed seven days of high-intensity interval training at ∼600m while sleeping each night in an altitude tent with an F1O2 of either ∼30.5% (SL) or ∼16.5% (ALT). There were two training sessions daily, each 90min in duration composed of 66 maximal efforts of 5–15 seconds with competition specific work:relief ratios (1:1, 1:3, 1:6). We used a double blind, repeated measures crossover design with a 2-wk washout period between treatments. A maximal graded exercise test (GXT = 100W; inc. 50W every 5min) was completed before and 2D after each training block. A dietician ensured that daily carbohydrate intake during the seven days of interval training was > 8g.kg−1.d−1. RESULTS Peak power during the GXT (Mean±SD) was lower (377±42 to 358±42 W, p = .17) following SL and unchanged (367±42 to 376±39 W, p = .41) following ALT. Peak power during the GXT after interval training was higher following ALT than following SL (19 W, 46 to −9W; 90%CL). Interval training did not result in any substantial changes in VO2pk, Lactatepk, or HRpk for either the ALT or SL trials. CONCLUSION Sleeping at altitude during a week of high-intensity cycling training is unlikely to impair, and may in fact improve cycling GXT performance. Future research is required to establish whether sleeping at higher altitudes or for longer durations interferes with performance adaptations to rigorous training. Supported by an Australian Sports Commission Grant

Effect Of High Intensity Cycle Training With Artificial Hypergravity During Bed Rest On Skeletal Muscle

Effect Of High Intensity Cycle Training With Artificial Hypergravity During Bed Rest On Skeletal Muscle

Effect Of High Intensity Cycle Training With Artificial Hypergravity During Bed Rest On Skeletal Muscle

Effect Of High Intensity Cycle Training With Artificial Hypergravity During Bed Rest On Skeletal Muscle

Altitude Tents Do Not Impair Performance Response To Short-term High-intensity Cycling Training

Altitude Tents Do Not Impair Performance Response To Short-term High-intensity Cycling Training

Desmin increases with high-intensity concentric contractions in humans.

To investigate the role desmin may play in muscular adaptation to exercise, we measured desmin protein content in the vastus lateralis muscle of seven untrained men in response to 8 weeks of high-intensity cycle training. Training involved 15-s sprints separated by rest for 5 min. Subjects began with four sprints twice per week, and progressed to six sprints three times per week. Peak power was measured before and after training with a 30-s maximal sprint test. Mean power during the first 15 s increased significantly after training (P < 0.05). Desmin and actin protein levels were determined by immunoblotting, from pretraining and posttraining muscle biopsies. Desmin protein levels were increased by 60% after training (P < 0.01), whereas actin protein levels did not change with training. We conclude that the cytoskeletal protein desmin increases in response to a high-tension, concentric-only load consequent to sprint training. Desmin appears to increase as the force generating capacity of the muscle increases. A reinforced desmin cytoskeleton may be necessary for increased force generation by the muscle.