The aim of this study is to examine the effect of heat and cold on the characteristics of skeleton muscles. 24 persons of different age and attitude to sport, men and women, have been examined (12 - using passive heating, 12 - using passive cooling). The rates of vertical jumps were registered (force, power, speed, height of jumps). The rates have been registered before and after cooling and heating procedures. Jumps with and without springing squats with angles of 90 and 135 degrees have been made. After the parameters were recorded, leg mucles were heated in 44 degrees water for 45 minutes or cooled two times in 15 degrees water for 15 minutes with 10 minutes break. Obtained results showed, that the contractile features of sceleton muscles after heating changed differently, the significant improvement of power of muscles was observed, the force of the contraction was stable. After reducing temperature the features of skeletal muscles (force, power, speed) have notably deteriorated. Slow muscle fibres showed greater response to the heating. The increment of power has been noticed. Faster and slower muscle fibres reacted equally to the cooling contraction speed and power have greatly reduced. The usage of elastic energy have not changed either at lower or higher temperatures. When applying physiotherapy means, such as heating or cooling, one has to take into account the dependence of contractile properties of the muscle on the temperature.

The majority of physiological processes and various other processes taking place in the body are closely related to changes in body temperature (Shellock & Prentince, 1985; Bennett, 1990). The temperature of the human body is constant throughout one’s life. It is approximately 37ºC and it constantly adjusts itself to changes in environment, relative air humidity, the level of radiation, atmosphere pressure and thermo isolation. During long-term physical load, in case of illness or in conditions of extreme body temperature may be in the range from 32ºC to 40ºC or even more (Wilmore & Costill, 2004). It could be hypothesized therefore that the muscle warmed prior to the load to be undertaken, when the leg is extended and flexed in the knee joint at high (500, 450o / s) and average (180o / s) speed depending on gender will increase muscle force and muscle capacity to a greater extent than the cooled muscle, but after lowering the temperature muscle resistance to fatigue will increase. Though considerable research has been done already certain questions still remain to be cleared up, namely: 1. how warming affects muscle fatigue and recovery of female knee extensors and flexors when the leg is being flexed and extended in the knee joint at the fixed 500o / s speed; 2. how muscle contraction function of female and male knee extensors and flexors depends on temperature when the leg is being flexed and extended in the knee joint at the fixed 450o / s and 180o / s peed. Though there... [to full text]