The Effect of Brief Skin Cooling on Isometric Muscle Strength
Condition: Cryotherapy Effect
Study type: Interventional

Summary: 
      There is sympathetic innervation of the muscular spindle. The application of cold to the skin
      provides an increase in sympathetic activity. In rehabilitation practice, short-term local
      cold is applied to the skin to provide motor facilitation. The aim of this study was to
      examine whether short-term local cold application provides an increase in isometric
      contractile strength and, if so, whether this effect is related to muscle spindle activity.
    

Detailed description: 
      Cold application is frequently used in sports medicine and rehabilitation due to its
      beneficial effects on the neuromuscular system. Its main beneficial effects are facilitating
      muscle contraction (motor facilitation), increasing isometric muscle force formation and
      reducing spasticity. The motor effects of cold application may vary depending on the
      application time, cooling agent (ice, ice water, cooling spray, etc.) and subcutaneous fatty
      tissue thickness. Short-term cold application can increase contraction force through motor
      facilitation. As the duration of cold application increases, the effects of cold that inhibit
      motor functions, such as gamma motor neuron inhibition, muscle spindle inhibition, and muscle
      conduction block, come to the fore. With this effect, it is used in the treatment of
      spasticity.

      Neurophysiological studies to explain the motor effects of cold application have generally
      focused on the monosynaptic muscle spindle-based reflex. The monosynaptic muscle
      spindle-based reflex activates muscle spindles and stimulates alpha motor neurons via Group
      Ia afferent nerves. This effect is also known as the servo-motor (servo-assistance) effect of
      the muscle spindle. The increase in the sensitivity of the muscle spindle can provide motor
      facilitation by strengthening the servo-assistance effect.

      It has been shown that the muscle spindle has sympathetic innervation. It has been shown that
      the cold stress test can be an alternative to the classical autonomic nerve test and can be
      used to test sympathetic system activation. Additionally, studies have shown that cold stress
      test, mental arithmetic, isometric contraction and muscle ischemia cause an increase in
      muscle spindle sensitivity through increased sympathetic activity.

      A literature review has shown that there is no study examining the mechanism underlying the
      effect of local cold application on motor facilitation. Demonstrating the effect of local
      cold application on increasing maximum contraction force through muscle spindle sensitivity
      is also important for clinical applications to be more effective and efficient. The aim of
      this study was to examine whether short-term local cold application increases isometric
      contraction force and, if there is an increase, whether this effect is related to muscle
      spindle activity.
    

Intervention name(s): Cheer; The cold pressure test
Intervention type(s): Procedure; Procedure
Intervention description(s): Maximum isometric contraction was performed with cheering.; Maximum isometric contraction was performed with the cold pressure test.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: soleus v-wave; sympathetic outflow; muscle spindle; cold stress test; sympathetic system; contractile force; motor facilitation