Abstract: Purpose the paper is to study the influence of resistance training on muscle strength and coordination ability under the conditions of unstable support. Methods 15 male subjects are used as testing objects to test the iEMG changes in the process of contraction and analyze the test results of their left RF and BF, TA, MG, ES and RA of loaded and non-loaded situations when half squatting under the two different supporting conditions (hard supporting surface and pad balance)through the ME6000 myoelectricity telemetry system. Results the iEMG values of the tested muscle groups of RF, BF, TA, MG, ES and RA under the condition of half squat with load and stable support are 30.78 + / - 7.97, 150.44 + / - 65.74, 338.11 + / - 114.93, 55.33 + / - 17.61, 758.44 + / - 248.98 and 56.89 + / - 20.49? V.s; while with unstable support, the values are 36.78 + / - 9.31, 170.78 + / - 58.84, 418.22 + / - 96.71, 85.89 + / - 42.79, 1012.89 + / - 210.38 and 63.33 + / - 22.53? V.s. Relative to the stable condition, the iEMGs of the tested muscle groups under unstable condition increase by 20%, 13.33%, 23.67%, 55.23%, 33.51% and 12.50%, with statistical significance between groups and the iEMG significantly of tibialis significantly greater than other tested muscle groups (P < 0.05). Conclusion unstable support interface increases the nervous system activity and muscle gathering level. The adjustment of the neuromuscular gathering mode is the basic guarantee to maintain the stability and coordination of the human body.

Key words: unstable support, resistance training, power, coordination