Rate of muscle tension development and release under extreme temperatures

Summary and Conclusions

Thirty-one male subjects squeezed a hand dynamometer as rapidly and as forcefully as possible, the effort being recorded on fast-moving paper. At the count of three the hand was released explosively. Two such testing sessions were held; following the first measurement of tension development and release the subject immersed his arm in a water bath. On one occasion it was at a temperature of 10° C, on the other of 46° C.

The subject then repeated the procedure with the hand ergograph. The force-time curves of the contraction were described mathematically by a three-component exponential equation. Very little difference existed in the rate parameters of the normal and hot conditions, but these parameters were markedly slowed by the application of cold. This was further reflected in the contributions that each component made to the total work integral. Similar results were obtained during the release phase; the rates were nearly identical for the normal and hot curves, but two or three times slower for the cold. The steady state force level, compared

with the normal, was significantly increased under the hot condition and significantly depressed under the cold.