			Home About us Contact

Eccentric Exercise (eccentric + exercise)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Metabolic and anti-inflammatory benefits of eccentric endurance exercise , a pilot study

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 4 2008
H. Drexel
ABSTRACT Background, Eccentric endurance exercise (e.g. hiking downwards) is less strenuous than concentric exercise (e.g. hiking upwards) but its potential to reduce cardiovascular risk is unknown. Materials and methods, We randomly allocated 45 healthy sedentary individuals (16 men and 29 women, mean age 48 years) to one of two groups, one beginning with two months of hiking upwards, the other with two months of hiking downwards the same route, with a crossover for a further two months. For the opposite way, a cable car was used where compliance was recorded electronically. The difference in altitude was 540 metres; the distance was covered three to five times a week. Fasting and postprandial metabolic profiles were obtained at baseline and after the two month periods of eccentric and concentric exercise, respectively. Results, Forty-two of the 45 participants completed the study; the compliance rate was therefore 93%. Compared with baseline, eccentric exercise lowered total cholesterol (by 4·1%; P = 0·026), low-density lipoprotein (LDL) cholesterol (by 8·4%, P = 0·001), Apolipoprotein B/Apolipoprotein A1 ratio (by 10·9%, P < 0·001), homeostasis model assessment of insulin resistance scores (by 26·2%, P = 0·017) and C-reactive protein (by 30·0%; P = 0·007); the magnitude of these changes was comparable to that of concentric exercise. Eccentric exercise improved glucose tolerance (by 6·2%, P = 0·023), whereas concentric exercise improved triglyceride tolerance (by 14·9%, P = 0·022). Conclusions, Eccentric endurance exercise is a promising new exercise modality with favourable metabolic and anti-inflammatory effects and is well applicable to sedentary individuals. [source]

The decrease in electrically evoked force production is delayed by a previous bout of stretch,shortening cycle exercise

ACTA PHYSIOLOGICA, Issue 1 2010
S. Kamandulis
Abstract Aim:, Unaccustomed physical exercise with a large eccentric component is accompanied by muscle damage and impaired contractile function, especially at low stimulation frequencies. A repeated bout of eccentric exercise results in less damage and improved recovery of contractile function. Here we test the hypotheses that (1) a prior stretch,shortening cycle (SSC) exercise protects against impaired muscle function during a subsequent bout of SSC exercise and (2) the protection during exercise is transient and becomes less effective as the exercise progresses. Methods:, Healthy untrained men (n = 7) performed SSC exercise consisting of 100 maximal drop jumps at 30 s intervals. The same exercise was repeated 4 weeks later. Peak quadriceps muscle force evoked by electrical stimulation at 15 (P15) and 50 (P50) Hz was measured before exercise, after 10, 25, 50 and 100 jumps as well as 1 and 24 h after exercise. Results:, P15 and P50 were higher during the initial phase of the repeated bout compared with the first exercise bout, but there was no difference between the bouts at the end of the exercise periods. P15 and P50 were again larger 24 h after the repeated bout. The P15/P50 ratio during exercise was not different between the two bouts, but it was higher after the repeated bout. Conclusion:, A prior bout of SSC exercise temporarily protects against impaired contractile function during a repeated exercise bout. The protection can again be seen after exercise, but the underlying mechanism then seems to be different. [source]

Heat shock protein translocation and expression response is attenuated in response to repeated eccentric exercise

ACTA PHYSIOLOGICA, Issue 3 2009
K. Vissing
Abstract Aim:, This study hypothesized that heat shock protein (HSP) translocation and upregulation is more probable to occur after eccentric exercise than after concentric exercise or repeated eccentric exercise. Methods:, Fourteen young, healthy, untrained male subjects completed two bench-stepping exercise bouts with 8 weeks between bouts, and were compared with a control group (n = 6). Muscle biopsies collected from m. vastus lateralis of both legs prior to and at 3 h, 24 h and 7 days after exercise were quantified for mRNA levels and/or for HSP27, ,,-crystallin and inducible HSP70 content in cytosolic and cytoskeletal protein fractions. Results:, The first bout of exercise reduced muscle strength and increased muscle soreness predominantly in the eccentric leg (P < 0.05). These responses were attenuated after the repeated eccentric exercise bout (P < 0.05), suggesting a repeated bout adaptation. Increases in inducible HSP70 and HSP27 protein content in cytoskeletal fractions were observed exclusively after eccentric exercise (P < 0.05). For HSP27, an approx. 10-fold upregulation after first-bout eccentric exercise was attenuated to a an approximately fourfold upregulation after the repeated eccentric exercise bout. mRNA levels for HSP70, HSP27 and ,,-crystallin were upregulated within approximately two to fourfold ranges at time points 3 and 24 h post-exercise (P < 0.05). This upregulation was induced exclusively by eccentric exercise but with a tendency to attenuated expression 3 h after the repeated eccentric exercise bout. Conclusion:, Our results show that HSP translocation and expression responses are induced by muscle damaging exercise, and suggest that such HSP responses are closely related to the extent of muscle damage. [source]

Effects of eccentric treadmill running on mouse soleus: degeneration/regeneration studied with Myf-5 and MyoD probes

ACTA PHYSIOLOGICA, Issue 1 2003
A.-S. Armand
Abstract Aim:, The aim of this report is to show that eccentric exercise under well-controlled conditions is an alternative model, to chemical and mechanical analyses, and analyse the process of degeneration/regeneration in mouse soleus. Methods:, For this, mice were submitted to a single bout of eccentric exercise on a treadmill down a 14° decline for 150 min and the soleus muscle was analysed at different times following exercise by histology and in situ hybridization in comparison with cardiotoxin-injured muscles. Results:, We analyse the regenerative process by detection of the accumulation of transcripts coding for the two myogenic regulatory factors, Myf-5 and MyoD, which are good markers of the activated satellite cells. From 24 h post-exercise (P-E), clusters of mononucleated Myf-5/MyoD-positive cells were detected. Their number increased up to 96 h P-E when young MyoD-positive myotubes with central nuclei began to appear. From 96 to 168 h P-E the number of myotubes increased, about 10-fold, the new myotubes representing 58% of the muscle cells (168 h P-E). Conclusion:, These results show that this protocol of eccentric exercise is able to induce a drastic degeneration/regeneration process in the soleus muscle. This offers the opportunity to perform biochemical and molecular analyses of a process of regeneration without muscle environment defects. The advantages of this model are discussed in the context of fundamental and therapeutical perspectives. [source]

Metabolic and anti-inflammatory benefits of eccentric endurance exercise , a pilot study

POPPING SARCOMERE HYPOTHESIS EXPLAINS STRETCH-INDUCED MUSCLE DAMAGE

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2004
David L Morgan
SUMMARY 1.,Exercise that involves stretching a muscle while active cause microscopic areas of damage, delayed onset muscle soreness and adaptation to withstand subsequent similar exercise. 2.,Longer muscle lengths are associated with greater damage and recent animal experiments show that it is the length relative to optimum that determines the damage. 3.,In humans, walking down stairs, taking two at a time, increases the length of the muscle during the lengthening and increases the delayed onset muscle soreness. 4.,The observed pattern of damage is consistent with explanations based on sarcomere length instabilities. 5.,The pattern of adaptation is consistent with the number of sarcomeres in series in a muscle being modulated by exercise, especially the range of muscle lengths over which eccentric exercise regularly occurs. [source]

IDENTIFYING ATHLETES AT RISK OF HAMSTRING STRAINS AND HOW TO PROTECT THEM

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2004
U Proske
SUMMARY 1.,One common soft-tissue injury in sports involving sprinting and kicking a ball is the hamstring strain. Strain injuries often occur while the contracting muscle is lengthened, an eccentric contraction. We have proposed that the microscopic damage to muscle fibres that routinely occurs after a period of unaccustomed eccentric exercise can lead to a more severe strain injury. 2.,An indicator of susceptibility for the damage from eccentric exercise is the optimum angle for torque. When this is at a short muscle length, the muscle is more prone to eccentric damage. It is known that subjects most at risk of a hamstring strain have a previous history of hamstring strains. By means of isokinetic dynamometry, we have measured the optimum angle for torque for nine athletes with a history of unilateral hamstring strains. We also measured optimum angles for 18 athletes with no previous history of strain injuries. It was found that mean optimum angle in the previously injured muscles was at a significantly shorter length than for the uninjured muscles of the other leg and for muscles of both legs in the uninjured group. This result suggests that previously injured muscles are more prone to eccentric damage and, therefore, according to our hypothesis, more prone to strain injuries than uninjured muscles. 3.,After a period of unaccustomed eccentric exercise, if the exercise is repeated 1 week later, there is much less evidence of damage because the muscle has undergone an adaptation process that protects it against further damage. We propose that for athletes considered at risk of a hamstring strain, as indicated by the optimum angle for torque, a regular programme of mild eccentric exercise should be undertaken. This approach seems to work because evidence from a group of athletes who have implemented such a programme shows a significant reduction in the incidence of hamstring strains. [source]