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Biomedical subjects

P Tesch

Publications and source records attributed to P Tesch.

At least 19 recordsLinked to original sources
PubMed2005

Effects of 84-days of bedrest and resistance training on single muscle fibre myosin heavy chain distribution in human vastus lateralis and soleus muscles.

AIM: This investigation determined the effects of 84 days of bedrest on the composition of myosin heavy chain (MHC) in single skeletal muscle fibres with and without a resistance-training countermeasure programme. METHODS: Muscle biopsies were obtained from the m. vastus lateralis (VL) and m. soleus (SOL) before and after 84 days of bedrest. While control (BR) subjects (VL n = 9; SOL n = 3) refrained from exercise, BRE subjects (VL n = 8; SOL n = 3) performed knee extensor and plantar flexor resistance exercise every third day. Approximately 110 fibres per sample were analysed for MHC composition using SDS-PAGE. RESULTS: BR-VL had 16 and 14% decreases (P < 0.05) in MHC I and IIa fibres, respectively. There were 10% increases (P < 0.05) in MHC I/IIa, IIa/IIx, I/IIa/IIx, and a approximately 30% increase (P < 0.05) in total hybrid fibres. BRE-VL showed a 15% reduction (P < 0.05) in MHC I fibres, no change in MHC IIa fibres, and a 13% increase (P < 0.05) in total hybrids. BR-SOL had a 19% decrease (P < 0.05) in MHC I fibres with a 22% increase in total hybrids. BRE-SOL showed no change in MHC composition across all fibre types. CONCLUSION: These data suggest that the exercise countermeasures programme prevented MHC shifts in the SOL and mitigated MHC shifts in the VL. Furthermore, in the VL it appears that the resistance training programme employed in this investigation during bedrest, emphasized the use of MHC IIa phenotype muscle fibres.

Adult↗
PubMed2002

A rat resistance exercise regimen attenuates losses of musculoskeletal mass during hindlimb suspension.

Exposure to microgravity and/or spaceflight causes dramatic losses in both muscle and bone mass. In normal gravity, resistance exercise has been effectively used to increase muscle and bone mass. We tested a novel form of resistance exercise training using flywheel technology as a countermeasure to offset the loss of musculoskeletal mass during 4 weeks of adult rat hindlimb suspension (HS), an unloading model of microgravity. Male, Sprague-Dawley rats (6-month old) were operantly conditioned to perform resistance exercise, and then randomly assigned to groups of sedentary control (CON), HS, and HS with resistance exercise training (HSRT; 2 sets of approximately 21 repetitions, 3 days week(-1) for 4 weeks during suspension). In soleus, HS resulted in lower (P < 0.05) muscle mass to body mass ratio (approximately 50% of controls) and rates of protein synthesis. HSRT significantly attenuated the loss of muscle mass in soleus muscle, and rates of protein synthesis for soleus were similar for HSRT and controls. There were no differences among groups for mass or rates of protein synthesis in extensor digitorum longus. In cancellous regions of the distal femur, HS resulted in significant reductions of bone mineral density (BMD), but this was restored to control levels with HSRT. Cortical regions of the femur were not different among HS, HSRT or control groups. Together, these data suggest that resistance training using flywheel technology may be a promising tool to attenuate losses of the musculoskeletal system during periods of hindlimb unloading.

Animals↗
PubMed2000

Sonographic evaluation of the thenar compartment musculature.

The thenar region was studied with ultrasonography in 10 healthy volunteers. All thenar muscles could be identified and their course followed entirely. In addition, their function could be assessed by scanning during unresisted or resisted active movements. Standard approach, normal appearance, and dynamic tests for each muscle are described.

Adolescent↗
PubMed1999

[Current knowledge on muscle training: endurance and strength yield complementary effects].

Both endurance and strength training are generally agreed to be necessary components of a balanced fitness programme. These two types of training are complementary; strength training improves neuromuscular function, prevents injuries, and is a prerequisite for effective endurance training. Whereas endurance training results in high energy expenditure during exercise, strength training, being associated with increased muscle mass, may result in increased energy expenditure at rest. In conjunction with endurance training, the most striking finding in skeletal muscle is its remarkable adaptability. Indeed, it is usually possible for the muscles to acquire the characteristics necessary to meet prevailing functional demands. This is true even if the demand is continuous contractile activity, 24 hours a day, week after week. The physiological effects of strength training are the result of hypertrophy of individual motor units, mostly comprising type II (fast-twitch) fibres, but are also secondary to neural changes affecting the recruitment and frequency modulation of motor units and co-ordination.

Energy Metabolism↗
PubMed1991

Physiological characteristics of elite judo athletes.

In order to provide some understanding of the physiological capacities underlying successful judo performance, representative values for a variety of physiological variables were determined in nationally ranked male (n = 18) and female (n = 9) judo athletes. Body composition, aerobic capacity, isokinetic elbow and knee flexor and extensor strength, and muscle fiber size and composition of the vastus lateralis were examined. Comparisons across weight divisions indicate that the values of many characteristics varied as a function of size. As weight division increased, relative VO2 decreased (r = -0.53 and -0.63 for males and females, respectively), % body fat increased (r = 0.64, 0.72), and the cross sectional areas of Type I (r = 0.55, 0.77) and Type IIA (r = 0.47, = 0.76) muscle fibers increased. Among females in particular, athletes in the higher weight divisions were stronger relative to LBM than those in the lower division. These results indicate that the physiological profiles of lower and upper weight division elite judo players differ markedly. It is suggested that the factors responsible for success may be specific to each weight division and may represent a compromise between making weight and maximizing physiological capacities and performance.

Adipose Tissue↗
PubMed1983

Semi-automatic blood lactate assay: experiences from an exercise laboratory.

A semi-automatic system based on flow injection analysis (FIA) for the transportation of small sample aliquots has been combined with fluorometric, enzymatic methods for blood lactate determination and has been described earlier. In the present study duplicate blood samples were obtained from exercising subjects to enable a comparison of lactate concentrations between neutralized and non-neutralized samples. Duplicate samples were also obtained to enable FIA lactate values to be compared to those obtained with a manual enzymatic method, and with a colorimetric method. No significant change was observed if the sample was not neutralized, enabling a more rapid sample turnover. The FIA method was reliable, with a coefficient of variation of 4.9% between duplicate blood samples. FIA lactate values were valid when compared to two other manual assays. FIA has been shown to be a rapid (60 samples x h-1) means of accurately determining blood lactate concentrations with 25 microliter blood samples and is of particular relevance to the exercise laboratory.

Automation↗
PubMed1982

Recovery of the electrocorticogram of canine brains after complete cerebral ischaemia at 37 degrees and 32 degrees C.

Complete cerebral ischemia was produced in totally isolated dog heads, perfused from a donor dog. The temperature of the isolated brain was kept constant before, during and after the complete ischaemia, at either 37 degrees C or 32 degrees C. At a brain temperature of 37 degrees C electrocortical potentials were found to reappear spontaneously as long as complete ischaemia did not exceed 50 min. In canine brains kept at a temperature of 32 degrees C no reappearance of spontaneous electrical activity occurred if ischaemia exceeded 100 min.

Animals↗
PubMed1982

Changes in muscle metabolites in females with 30-s exhaustive exercise.

The purpose of this study was to quantify the changes in selected intramuscular metabolites associated with non-oxidative energy metabolism after performance of the Wingate Test (WT), a widely used, exhaustive, 30-s cycle test of short-time muscular power. Muscle biopsies were taken from the m. vastus lateralis of nine female physical education students at rest and immediately after performance of the WT. The concentrations of adenosine triphosphate (ATP), creatine phosphate (CP), lactate, and glycogen were determined. The ATP decreased from 20.9 to 13.8; CP decreased from 62.7 to 25.1; lactate increased from 9.0 to 60.5; and glycogen decreased from 360 to 278 (all concentrations are mmol X kg-1 dry muscle). The absolute changes in CP and lactate were not as large as those reported in other exercise studies. Based on the metabolite changes, it was concluded that the WT is a satisfactory test of the maximal muscular power that can be generated from non-oxidative metabolism, but that the 30-s duration of the test probably does not tax the maximal capacity of such energy metabolism.

Adenosine Triphosphate↗
PubMed1981

Muscle strength and fatigue after selective glycogen depletion in human skeletal muscle fibers.

Two groups of male subjects were studied to examine the effects of different exercise protocols on performance of an isokinetic, short-time strength test, the performance of which is related to fast twitch (FT) muscle fiber recruitment. The laboratory group (LG) (n = 10) cycled (30 min, 70% VO2 max), ran (75 min), and performed repeated bouts of "sprint" cycling and rapid, maximal contractions of the quadriceps. The marathon group (MG) (n = 7) participated in and completed Stockholm's Marathon 1979. A strength test was performed before and within 1-2 h after completion of the group exercise protocol. The m. vastus lateralis was biopsied and muscle fibers classified as slow twitch (ST) or FT. After periodic acid-Schiff staining fibers were qualitatively classified as to glycogen content. In LG significant glycogen depletion occurred in both fiber types and in MG predominantly ST fibers were exhausted of glycogen after the exercise protocol. The glycogen exhaustion from both fiber types in LG was associated with impaired maximal muscular strength produced during a single dynamic contraction, as well as with reduced muscle fatigue patterns. When glycogen exhaustion was induced in ST muscle fibers only in the MG, no impairment was observed for maximal muscular strength but fatigue during 50 consecutive contractions was significantly increased.

Adult↗
PubMed1981

Increase of lipoprotein-lipase activity in skeletal muscle during heavy exercise. Relation to epinephrine excretion.

As part of the training programme for Swedish elite soldiers, a 10 day march is carried out with a heavy pack under active-service conditions. Six soldiers volunteered to take part in an investigation on the energy consumption with special regard to the lipid metabolism at different levels of physical effort. The degree of physical work was evaluated by continuous heart-rate recording and analysis of the excretion of epinephrine and norepinephrine in the urine. Fasting values of triglycerides and free fatty acids in blood plasma were determined and muscle biopsies (taken in the morning and in the afternoon) were analysed for lipoprotein-lipase (LPL) activity. After an overnight fast the free fatty acids were increased only in the mornings following days of heavy physical work. The plasma triglyceride concentrations were lowest in a morning proceeded by 3 days of heavy work. The muscle LPL activity in the morning was highest after a day of heavy work and lowest after days of rest. During days of heavy work this activity increased and was higher in the afternoon than in the morning. Muscle LPL activity in the afternoon was closely related to urinary excretion of epinephrine. The data indicate that LPL activity is elevated in the working skeletal muscle increasing the access of fatty acids. The degree of elevation is related to the degree of effort as described by the urinary excretion of morning. Muscle LPL activity in the afternoon was closely related to urinary excretion of epinephrine. The data indicate that LPL activity is elevated in the working skeletal muscle increasing the access of fatty acids. The degree of elevation is related to the degree of effort as described by the urinary excretion of morning. Muscle LPL activity in the afternoon was closely related to urinary excretion of epinephrine. The data indicate that LPL activity is elevated in the working skeletal muscle increasing the access of fatty acids. The degree of elevation is related to the degree of effort as described by the urinary excretion of epinephrine.

Catecholamines↗
PubMed1981

Relationships between leg muscle fiber type distribution and leg exercise performance.

The object of the present experiments was to study the impact of muscle fiber type composition on "aerobic" and "anaerobic" performance capacities. Muscle fiber type composition was determined on biopsies from the m. vastus lateralis of 29 healthy males, consisting of sedentary subjects, physical education students, and short- and long-distance runners. The subjects performed: (a) a 30-s all-out ride on a cycle ergometer; b) a short-term (60 s), isokinetic, one-leg exercise test, (c) a 40-m sprint run; d) a 300 m run; and (e) a 2000-m run. Correlations between muscle fiber composition, expressed as % fast twitch (FT) fibers on one hand, and peak power, maximal peak torque, power decrease, and peak torque decrease in the laboratory tests were significant (P less than O.001) for the trained subjects but not for the sedentaries. Average speed during the 40-m sprint and the 2000-m run was positively (P less than 0.001) and negatively (P less than 0.001) related, respectively, to % FT in the trained subjects whereas no such correlations were present for sedentaries. It is suggested that fiber type composition in trained males is one factor contributing to ability to perform short-term as well as endurance exercise. This statement may not be true for the general population.

Adolescent↗
PubMed1979

EMG frequency spectrum, muscle structure, and fatigue during dynamic contractions in man.

Fatigue of the vastus lateralis muscle was studied in healthy well-conditioned students, who differed considerable regarding their muscle fibre type distribution. Muscle force decline during repeated maximum voluntary knee extensions at a constant angular velocity (180 degree X s-1 or rad X s-1), using isokinetic equipment, was taken as the criterion for the degree of fatigue. In an attempt to study quantitative as well as qualitative changes in the EMG pattern, integrated EMG (IEMG) and the frequency of the mean power (MPF), computed from the power spectral density function (PSDF), were analysed. It was found that individuals with muscles made up of a high proportion of fast twitch (FT) muscle fibres demonstrated higher peak knee extension torque, and a greater susceptibility to fatigue than did individuals with muscles mainly composed of slow twitch (ST) muscle fibres. An IEMG decline (p less than 0.01) was demonstrated during 100 contractions in individuals rich in FT fibres. Only a slight, but not significant, reduction in IEMG occurred in individuals with high percentage of ST fibres. Concomitantly, MPF decreased (p less than 0.001) in individuals with a high percentage of FT fibres, while their opposites demonstrated only a slight decrease (non-significant). It is suggested that muscle conctraction failure might also be related to qualitative changes in the motor unit recruitment pattern, and that these changes occur more rapidly in muscles composed of a high proportion of FT muscle fibres than in muscles composed to a high proportion of ST fibres.

Action Potentials↗
PubMed1979

Central and peripheral circulation in relation to muscle-fibre composition in normo- and hyper-tensive man.

1. Fibre composition in the vastus lateralis muscle, and blood pressure, were determined in age-matched normotensive (n = 22) subjects and previously untreated patients (n = 19) with essential hypertension. 2. In all subjects the muscle fibres were classified, as fast-twitch (FT) and slow-twitch (ST), and blood pressure was recorded. Eleven patients and seven of the normotensive subjects participated in an extended haemodynamic study with intra-arterial pressure measurements and determinations of leg blood flow. 3. In both normo- and hyper-tensive subjects, ambulant and intra-arterial blood pressure and leg vascular resistance were negatively correlated to the percentage of ST fibres; no significant correlation was found to total leg blood flow. 4. The findings show that muscles with a high proportion of FT fibres have a higher resistance than muscles rich in ST fibres and suggest that the type of fibre in skeletal muscle might be of importance for the development of the hypertensive disease.

Adult↗
PubMed1978

Relationship between lactate accumulation, LDH activity, LDH isozyme and fibre type distribution in human skeletal muscle.

Lactate concentration, total LDH activity and muscle-specific LDH isozymes were determined in pools of the two main types of human skeletal muscle fibres. Analyses were made from biopsy specimens obtained after intense dynamic exercise lasting approximately 30 s. Lactate concentration, total LDH activity and muscle-specific LDH activity displayed higher average values for FT (fast twitch) fibres than for ST (slow twitch) fibres. In addition, positive correlations were found both between the individual percentage of FT fibres and muscle lactate concentration and between lactate concentration and total LDH activity and muscle-specific LDH activity respectively.

Adult↗
PubMed1978

Isometric strength performance and muscle fibre type distribution in man.

Maximal isometric one-leg strength (MIS) was determined in 31 physical education students displaying a wide range in muscle fibre type distribution (21-79% fast twitch (FT) muscle fibres) in their vastus lateralis muscles. A linear positive correlation was found between MIS and the relative distribution of FT fibres (p less than 0.001). This should mean that not only muscle mass involved but also the quality of muscle will be decisive for the ability to develop high isometric strength.

Adult↗