Poor correlations between isometric tests and dynamic performance: relationship to muscle activation

The purpose of this research was to perform isometric tests at two joint angles and examine their relationship to dynamic performance. In addition, electromyograph data were collected from the triceps brachii and pectoralis major muscles to compare underlying neural characteristics between the isometric tests and dynamic movement. A group of 24 healthy male subjects performed two isometric tests in a bench press position, at elbow angles of 90 and 120°. From these data, the maximal force and rate of force development were determined. In addition, each subject performed a seated medicine ball throw as a measure of dynamic upper body performance. Correlations showed that isometric measurements of force (r = 0.47–0.55) and rate of force development (r = 0.08–0.31) were poor predictors of dynamic performance. The angle of isometric assessment had little effect on the relationship between the tests and measurements of performance. The myo-electric data was processed in terms of the integrated electromyogram and the Fourier transformed frequency spectrum. These data demonstrated differences in the neural activation patterns of the musculature, between the isometric 90° test and the medicine ball throw. The poor relationship between isometric tests and medicine ball performance was consequently, at least partially, attributed to differing motor unit activation patterns between isometric and dynamic movement. The results of this research strongly suggest that isometric tests have limited value when assessing dynamic upper body performance.

[1]  P. Lago,et al.  Effect of motor-unit firing time statistics on e.m.g. spectra , 1977, Medical and Biological Engineering and Computing.

[2]  J T Viitasalo,et al.  Reproducibility of measurements of selected neuromuscular performance variables in man. , 1980, Electromyography and clinical neurophysiology.

[3]  P V Komi,et al.  Relationships between training volume, physical performance capacity, and serum hormone concentrations during prolonged training in elite weight lifters. , 1987, International journal of sports medicine.

[4]  J. Clasey,et al.  The effect of the rate of muscle contraction on the force-time curve parameters of male and female subjects. , 1990, Research Quarterly for Exercise and Sport.

[5]  Gregory J. Wilson,et al.  Isometric Assessment of Muscular Function: The Effect of Joint Angle , 1995 .

[6]  J. Macdougall,et al.  Physiological testing of the high-performance athlete , 1993 .

[7]  A. Fuglsang-Frederiksen,et al.  The motor unit firing rate and the power spectrum of EMG in humans. , 1988, Electroencephalography and clinical neurophysiology.

[8]  Yasuo Kawakami,et al.  Differences in activation patterns in elbow flexor muscles during isometric, concentric and eccentric contractions , 1993, European Journal of Applied Physiology and Occupational Physiology.

[9]  M. Okada.  Effect of muscle length on surface EMG wave forms in isometric contractions , 2004, European Journal of Applied Physiology and Occupational Physiology.

[10]  M. Ikäheimo,et al.  Impaired Left Ventricular Diastolic Function in Athletes After Utterly Strenuous Prolonged Exercise , 1987, International journal of sports medicine.

[11]  J T Viitasalo,et al.  Seasonal fluctuations of force production in high jumpers. , 1984, Canadian journal of applied sport sciences. Journal canadien des sciences appliquees au sport.

[12]  P V Komi,et al.  Electromyographic and Force Production Characteristics of Leg Extensor Muscles of Elite Weight Lifters During Isometric, Concentric, and Various Stretch-Shortening Cycle Exercises , 1986, International journal of sports medicine.

[13]  Günter,et al.  Aspects of strength training in athletics , 2006 .

[14]  R U Newton,et al.  The optimal training load for the development of dynamic athletic performance. , 1993, Medicine and science in sports and exercise.

[15]  Viitasalo Jt,et al.  Effects of pretension on isometric force production. , 1982 .

[16]  E. Tichauer.  Anatomic Guide for the Electromyographer , 1977 .

[17]  R. Person,et al.  Rhythmic activity of a group of human motoneurones during voluntary contraction of a muscle. , 1974, Electroencephalography and clinical neurophysiology.

[18]  J T Viitasalo.  Effects of pretension on isometric force production. , 1982, International journal of sports medicine.

[19]  K. Häkkinen,et al.  Neuromuscular Fatigue and Recovery in Male and Female Athletes during Heavy Resistance Exercise , 1993, International journal of sports medicine.

[20]  D. Sale,et al.  Hypertrophy without increased isometric strength after weight training , 2004, European Journal of Applied Physiology and Occupational Physiology.

[21]  A. Murphy,et al.  Use of the iso-inertial force mass relationship in the prediction of dynamic human performance , 2004, European Journal of Applied Physiology and Occupational Physiology.

[22]  Dušan Ristanović,et al.  The relationship between muscle kinetic parameters and kinematic variables in a complex movement , 1989, European Journal of Applied Physiology and Occupational Physiology.

[23]  Warren B. Young,et al.  The Effect of Voluntary Effort to Influence Speed of Contraction on Strength, Muscular Power, and Hypertrophy Development , 1993 .