Adaptive changes in motor unit contractile properties to endurance training

• Autorzy: Krysciak K. , Krysciak J. , Lochynski D. , Kaczmarek D. , Drzymala-Celichowska H. , Krutki P. , Celichowski J.
• Języki publikacji: EN

Abstrakty

EN

BACKGROUND AND AIMS: Endurance training is based on a repeated, prolonged activation of a large number of muscles. It causes morphological, biochemical and metabolic changes in the muscles and the nervous system. However, there are no data concerning changes in motor unit (MU) contractile properties following endurance training. METHODS: 61 male rats were assigned to 4 groups, untrained – control (C), and 3 groups trained on a treadmill, 5 days a week for 2 weeks (2W), 4 weeks (4W) or 8 weeks (8W). The special protocol determined duration and speed of locomotion in the consecutive days of the training. Finally, rats of the 2W group covered average distance of 5.5 km, 4W of 21 km, and 8W of 56 km. Afterwards, functionally isolated MUs of the medial gastrocnemius muscle were electrophysiologically investigated. RESULTS: The mean body mass of rats of all trained groups was lower in comparison to the C group, but no differences between 2W, 4W and 8W groups were noted. The muscle mass and the muscle-to-body mass ratio were not different between groups. The proportion of fast resistant (FR) MUs was higher, while of fast fatigable (FF) lower in all trained groups, in comparison to the C group. The relative number of slow (S) MUs increased only in the 8W group. MU contractile properties were changed mainly in FR MUs and included: lower contraction and half-relaxation times, lower twitch forces, higher tetanus forces and lower twitch-to-tetanus ratio. Few adaptive changes were noted also for S MUs of trained animals: lower twitch and tetanus forces as well as lower twitch-to-tetanus ratio. For FR and S MUs of all trained groups the force decrease within four minutes of the fatigue test was considerably slower or even completely abolished, which was reflected in the increased fatigue indexes. CONCLUSION: The main adaptive changes appeared early and then slowly increased within the endurance training. Supported by the National Science Center grant 2013/09/B/ NZ7/02555.

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2015
• Tom: 75
• Numer: Supl.
• Opis fizyczny: p.S74

Twórcy

autor

Krysciak K.

• Department of Neurobiology, University School of Physical Education, Poznan, Poland

autor

Krysciak J.

• Department of Physiology, University School of Physical Education, Poznan, Poland

autor

Lochynski D.

• Department of Neurobiology and Department of Motor Rehabilitation; University School of Physical Education, Poznan, Poland

autor

Kaczmarek D.

• Division of Biochemistry, Department of Neurobiology, University School of Physical Education, Poznan, Poland

autor

Drzymala-Celichowska H.

• Division of Biochemistry, Department of Neurobiology, University School of Physical Education, Poznan, Poland

autor

Krutki P.

• Department of Neurobiology, University School of Physical Education, Poznan, Poland

autor

Celichowski J.

• Department of Neurobiology, University School of Physical Education, Poznan, Poland