Sökning: "concentric and isometric and eccentric muscle actions"

Hittade 5 avhandlingar innehållade orden concentric and isometric and eccentric muscle actions.

1. 1. On spinal mechanisms for reflex control in man : modulation of Ia-afferent excitation with changes in muscle length, activation level and fatigue

   Författare :Maria M. Nordlund; Gymnastik- och idrottshögskolan; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :Electromyography; eccentric; concentric; presynaptic inhibition; H-reflex; central fatigue; twitch interpolation; muscle spindle; Medicin Teknik; Medicine Technology; Electromyography; eccentric; concentric; presynaptic inhibition; H-reflex; central fatigue; twitch interpolation; muscle spindle;

   Sammanfattning : To control muscle force, neural activation has to take alterations in muscle mechanics into account. This thesis assesses modulations in excitatory efficacy of Ia-afferents during muscle length changes at different levels of voluntary activation and during fatigue. LÄS MER

3. 2. Neuromuscular aspects of eccentric knee extensor actions : effects of electrical stimulation, age, gender and training

   Författare :Jan Seger; Alf Thorstensson; Roger Enoka; Gymnastik- och idrottshögskolan; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Physiology; Fysiologi; children; concentric; eccentric; efficiency; electrical stimulation; electromyography; growth; inhibition; isokinetic; specificity; strength; training;

   Sammanfattning : The overall aim of this thesis was to study the effects of electrical stimulation, age, gender and training on the torque- and EMG-velocity relationships during eccentric knee extensor muscle actions in man. An isokinetic custom-built dynamometer was evaluated and used throughout the thesis. LÄS MER

4. 3. Acute and early chronic responses to resistance exercise using flywheel or weights

   Författare :Lena Norrbrand; Per Tesch; Ola Eiken; Per Aagaard; Mittuniversitetet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; electromyography; flywheel; magnetic resonance imaging; resistance exercise; Sports; Idrott;

   Sammanfattning : Resistance exercise using weights typically offers constant external load during coupled shortening (concentric) and lengthening (eccentric) muscle actions in sets of consecutive repetitions until failure. However, the constant external load and the inherent capability of skeletal muscle to produce greater force in the eccentric compared with the concentric action, would infer that most actions are executed with incomplete motor unit involvement. LÄS MER

5. 4. Effects of unloading on skeletal muscle mass and function in man

   Författare :Hans Berg; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :Atrophy; bedrest; concentric and isometric and eccentric muscle actions; disuse; electromyography; fatigue; fiber types and size; humans; inactivity; maximal voluntary force; recovery; skeletal muscle cross-sectional area; strength; suspension; tomog;

   Sammanfattning : An experimental human model of skeletal muscle unloading of one lower limb and confined bedrest were employed to quantitate the adaptive responses to 10 days, 4 or 6 wk of unloading in healthy humans on quadricep skeletal muscle mass and function. Muscle cross-sectional area (CSA) was assessed using tomographic imaging (CT, MRI). LÄS MER

7. 5. Acute and early chronic responses to resistance exercise using flywheel or weights

   Författare :Lena Norrbrand; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :;

   Sammanfattning : Weight training typically offers constant external load during coupled shortening (concentric) and lengthening (eccentric) muscle actions in sets of consecutive repetitions until failure. However, skeletal muscle inherently has the capability to produce greater force in the eccentric compared with the concentric action, which allows for greater loading during the eccentric action, i. LÄS MER