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  • 1
    Electronic Resource
    Electronic Resource
    Recovery from short term intense exercise: Its relation to capillary supply and blood lactate concentration (1983)
    Springer
    European journal of applied physiology 52 (1983), S. 98-103 
    Details
    ISSN: 1439-6327
    Keywords: Fatigue ; Mean fiber area ; Muscle fiber types ; Capillary density ; Peak torque
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Muscle force recovery from short term intense exercise was examined in 16 physically active men. They performed 50 consecutive maximal voluntary knee extensions. Following a 40-s rest period five additional maximal contractions were executed. The decrease in torque during the 50 contractions and the peak torque during the five contractions relative to initial torque were used as indices for fatigue and recovery, respectively. Venous blood samples were collected repeatedly up to 8 min post exercise for subsequent lactate analyses. Muscle biopsies were obtained from m. vastus lateralis and analysed for fiber type composition, fiber area, and capillary density. Peak torque decreased 67 (range 47–82%) as a result of the repeated contractions. Following recovery, peak torque averaged 70 (47–86%) of the initial value. Lactate concentration after the 50 contractions was 2.9±1.3 mmol·l−1 and the peak post exercise value averaged 8.7±2.1 mmol·l−1. Fatigue and recovery respectively were correlated with capillary density (r=−0.71 and 0.69) but not with fiber type distribution. A relationship was demonstrated between capillary density and post exercise/peak post exercise blood lactate concentration (r=0.64). Based on the present findings it is suggested that lactate elimination from the exercising muscle is partly dependent upon the capillary supply and subsequently influences the rate of muscle force recovery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429033
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  • 2
    Electronic Resource
    Electronic Resource
    The influence of muscle metabolic characteristics on physical performance (1985)
    Springer
    European journal of applied physiology 54 (1985), S. 237-243 
    Details
    ISSN: 1439-6327
    Keywords: Fiber type composition ; Capillary density ; Enzyme activities ; Aerobic power and capacity ; Muscle strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study describes the influence of muscle fiber type composition, enzyme activities and capillary supply on muscle strength, local muscle endurance or aerobic power and capacity. Muscle biopsies were obtained from m. vastus lateralis in thirteen physically active men. Histochemical staining procedures were applied to assess the percentage of fast twitch (FT) fibers, muscle fiber area, and capillary density. Also, the activity of citrate synthase (CS), creatine kinase (CK), hexokinase (HK), lactate dehydrogenase (LDH), and phosphofructokinase (PFK) were analysed using fluorometrical assays. Peak torque at ‘low’ and ‘high’ angular velocities was measured during leg extension. Similarly, muscle fatigue (e. g. peak torque decline) and recovery from a short-term exercise task were measured during maximal, voluntary consecutive leg extensions. Aerobic power ( $$\dot V_{{\text{O}}_{{\text{2max}}} }$$ ) and aerobic capacity (e.g. onset of blood lactate concentration; OBLA), as defined by a blood lactate concentration of 4 mol · l−1 were measured during cycling. Peak torque at a high angular velocity was positively correlated with % FT area (p〈0.001). Fatigue and recovery were correlated with LDH · CS−1 (p〈0.001). WOBLA was best correlated with PFK and PFK · CS−1 (p〈0.001). Hence, muscle strength was partly determined by fiber type composition whereas local muscle endurance, recovery and aerobic capacity reflect mainly capillary supply and the activity of key enzymes involved in aerobic and anaerobic metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00426139
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  • 3
    Electronic Resource
    Electronic Resource
    Bilateral eccentric and concentric torque of quadriceps and hamstring muscles in females and males (1989)
    Springer
    European journal of applied physiology 59 (1989), S. 227-232 
    Details
    ISSN: 1439-6327
    Keywords: Torque velocity relationship ; Human skeletal muscle mechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study assessed maximum eccentric (ECC) and concentric (CON) torque of quadriceps (QUAD) and hamstring (HAM) muscle groups in healthy females (n=13) and males (n=27). Peak torques (PT) of bilateral muscle actions were recorded at constant angular velocities of 0.52, 1.57 and 2.61 rad·s−1. The QUADcon and HAMcon PT decreased (p〈0.05) with increasing angular velocity. The QUADecc and HAMecc PT increased (p〈0.05) in females, whereas QUADecc PT decreased (p〈0.05) and HAMecc PT showed no change in males. In general, ECC PT was higher (p〈0.05) than CON PT and QUAD PT was higher (p〈0.05) than HAM PT, for any given angular velocity. Males displayed higher (p〈0.05) PT than females but when PT were adjusted for body mass the sex differences in QUADcon and HAMcon were reduced (p〈0.05), whereas the differences in QUADecc and HAMecc were abolished. The CON and ECC PT were, on average, 60% and 41% greater, respectively, in males than in females. The corresponding differences, when adjusted for body mass, were 23% and 8%. ECC:CON PT for QUAD were higher (p〈0.05) in females than in males. CON and ECC HAM:QUAD PT ratio increased (p〈0.05), as a function of velocity. This study suggests, that bilateral ECC PT is higher than CON PT and CON HAM:QUAD PT ratio is higher than ECC HAM:QUAD PT ratio. Moreover, females and males display different ECC torque-velocity patterns, whereas CON torquevelocity patterns are similar and females possess greater QUADecc PT relative to QUADcon PT than males.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386192
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  • 4
    Electronic Resource
    Electronic Resource
    Muscle metabolite accumulation following maximal exercise (1984)
    Springer
    European journal of applied physiology 52 (1984), S. 243-246 
    Details
    ISSN: 1439-6327
    Keywords: Lactate ; Glycogen ; ATP ; Creatine phosphate ; Glucose ; Glucose-6-phosphate ; Arm exercise
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Five elite flatwater kayak paddlers were studied during indoor simulated 500 and 10,000-m races, with performance times of 2 and 45 min, respectively. Muscle biopsies were obtained from the midportion of m. deltoideus immediately pre and post exercise. Concentrations of adenosine triphosphate (ATP), creatine phosphate (CP), glucose, glucose-6-phosphate (G-6-P), glycogen, and lactate were subsequently determined. Short term exercise resulted in statistically significant increases in glucose (P〈0.001), G-6-P (P〈0.05) and lactate (P〈0.01) concentration concomitant with decreased CP (P〈0.05) and glycogen (P〈0.01). Following prolonged exercise, a non-significant elevation in glucose and a reduction (P〈0.01) in glycogen were demonstrated. Evidently the metabolic demands for kayak competitions at 500 and 10,000 m are different. Thus, the energy contribution from glycolytic precursors and the anaerobic component is of greater relative importance in short distances than in exercise of long duration. A generalization of the findings to other athletic events of varying distances is proposed. The present data on arm-exercise is consistent with previous findings obtained in connection with leg exercises.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00433400
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  • 5
    Electronic Resource
    Electronic Resource
    Muscle hypertrophy in bodybuilders (1982)
    Springer
    European journal of applied physiology 49 (1982), S. 301-306 
    Details
    ISSN: 1439-6327
    Keywords: Muscle fiber types ; Muscle fiber size ; Muscle hypertrophy ; Muscle strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Muscle biopsy samples were obtained from m. vastus lateralis and m. deltoideus of three high caliber bodybuilders. Tissue specimens were analysed with respect to relative distribution of fast twitch (FT) and slow twitch (ST) fiber types and different indices of fiber area. In comparison to a reference group of competitive power/weight-lifters the following tendencies were observed: the percentage of FT fibers was less, mean fiber area was smaller and selective FT fiber hypertrophy was not evident. Values for fiber type composition and fiber size were more similar to values reported for physical education students and non-strength trained individuals. The results suggest that weight training induced muscle hypertrophy may be regulated by different mechanisms depending upon the volume and intensity of exercise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00441291
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  • 6
    Electronic Resource
    Electronic Resource
    Motor unit fibre density in extremely hypertrophied skeletal muscles in man (1986)
    Springer
    European journal of applied physiology 55 (1986), S. 130-136 
    Details
    ISSN: 1439-6327
    Keywords: Single fibre electromyography ; Muscle biopsies ; Bodybuilders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single fibre electromyography (SFEMG) was performed on the left quadriceps, extensor digitorum communis, and biceps brachii muscles of four highly trained bodybuilders (BB). Muscle fibre areas, as assesed from biopsy samples, were similar in the BB as in age-matched habitually active male controls despite large differences in limb circumferences. This indicates a greater muscle fibre number in BB. An abnormally high muscle fibre density (FD) was recorded in two subjects exposed to extremely severe exercise for 14 years or longer, while those with normal FDs had been training extensively for a considerably shorter time (4–6 years). The abnormal FD was due either to an ephaptic transmission of action potentials between adjacent muscle fibres, or a muscle fibre hyperplasia, or most probably a combination of both, in response to a long-term functional overload. From the present results one cannot say whether the suggested muscle fibre hyperplasia had any major influence on the muscle hypertrophyper se, since all BB possesed large muscle volumes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00714994
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  • 7
    Electronic Resource
    Electronic Resource
    Muscle metabolism during intense, heavy-resistance exercise (1986)
    Springer
    European journal of applied physiology 55 (1986), S. 362-366 
    Details
    ISSN: 1439-6327
    Keywords: ATP, CP, glucose ; Glucose-6-phosphate ; Lactate ; Glycogen ; α-glycerophosphoate ; Strength training
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The objective of this study was to examine the muscle metabolic changes occurring during intense and prolonged, heavy-resistance exercise. Muscle biopsies were obtained from the vastus lateralis of 9 strength trained athletes before and 30 s after an exercise regimen comprising 5 sets each of front squats, back squats, leg presses and knee extensions using barbell or variable resistance machines. Each set was executed until muscle failure, which occurred within 6–12 muscle contractions. The exercise: rest ratio was approximately 1∶2 and the total performance time was 30 min. Concentrations of adenosine triphosphate (ATP), creatine phosphate (CP), creatine, glycogen, glucose, glucose-6-phosphate (G-6-P), α-glycerophosphate (α-G-P) and lactate were determined on freeze-dried tissue samples using fluorometric assays. Blood samples were analyzed for lactate and glucose. The exercise produced significant reductions in ATP (p〈0.01) and CP (p〈0.001), while α-G-P more than doubled (p〈0.05), glucose increased tenfold (p〈0.001) and G-6-P fourfold (p〈0.001). Muscle lactate concentration at cessation of exercise averaged 17.3 mmol · kg−1 w.w. Glycogen concentration decreased (p〈0.001) from 160 to 118 mmol · kg−1 w. w. It is concluded that high intensity, heavy resistance exercise is associated with a high rate of energy utilization through phosphagen breakdown and activation of glycogenolysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422734
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  • 8
    Electronic Resource
    Electronic Resource
    Blood lactate accumulation during arm exercise in world class kayak paddlers and strength trained athletes (1984)
    Springer
    European journal of applied physiology 52 (1984), S. 441-445 
    Details
    ISSN: 1439-6327
    Keywords: Arm crank ergometer ; Bodybuilders ; Exercise tolerance ; Weight-/power-lifters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Blood lactate accumulation was studied during progressive arm exercise in male and female world class kayak paddlers (K♂, K♀,n=11), weight-/power-lifters (WL/PL,n=6), bodybuilders (BB,n=8) and non-athletes (NA,n=6). The heavy resistance trained athletes exhibited greater upper-body muscle volume than the other subject groups. During low submaximal exercise intensities, blood lactate concentrations were significantly lower both in male and female kayakers compared with WL/PL, BB, and NA. Mean values at 120 W were 1.9 (K♂), 2.1 (K♀), 4.8 (WL/PL), 4.5 (BB), and 5.1 (NA) mmol·l−1. At higher power outputs the difference between females and non-kayakers diminished, while the difference between K♂ and all other groups increased. Exercise tolerance was greatest in K♂ and was equal among the other groups. Our results suggest that factors other than the muscle mass per se involved in exercise are responsible for the blood lactate response during this kind of work. Moreover, the physiological response observed in kayakers probably represents the upper limit of man's ability to perform continuous progressive arm-cranking exercise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00943377
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  • 9
    Electronic Resource
    Electronic Resource
    Skeletal muscle fiber type composition and performance during repeated bouts of maximal, concentric contractions (1988)
    Springer
    European journal of applied physiology 58 (1988), S. 81-86 
    Details
    ISSN: 1439-6327
    Keywords: Human skeletal muscle ; Restricted oxygen supply ; Fatigue ; Recovery ; Intermittent exercise
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Force output and fatigue and recovery patterns were studied during intermittent short-term exercise. 27 men performed three bouts of 30 maximal unilateral knee extensions on 2 different occasions. Blood flow was maintained or occluded during recovery periods (60 s). Blood flow was restricted by inflating a pneumatic cuff placed around the proximal thigh. Muscle biopsies from vastus lateralis were analyzed for identification of fast twitch (FT) and slow twitch (ST) fibers and relative FT area. Peak torque decreased during each bout of exercise and more when blood flow was restricted during recovery. Initial peak torque (IPT) and average peak torque (APT) decreased over the three exercise bouts. This response was 3fold greater without than with blood flow during recovery. IPT and APT decreased more in individuals with mainly FT fibers than in those with mainly ST fibers. It is suggested that performance during repeated bouts of maximal concentric contractions differs between individuals with different fiber type composition. Specifically, in high intensity, intermittent exercise with emphasis on anaerobic energy release a high FT composition may not necessarily be advantageous for performance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00636607
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