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Effects of the Tonic Neck Reflex in the Bench Press.

Berger Richard A.; Smith, Kirby J.
Journal of Strength & Conditioning Research: November 1991
Article: PDF Only

The effects of the tonic neck reflex (TNR) on power in the bench press lift were examined according to gender and in reference to head positions of ventroflexion, neutral and dorsiflexion. A resistance load of 90 percent of one-repetition maximum (1 RM) was lifted with maximum speed at each head position. Subjects were college men (n = 4, height = 172.7 +/- 7.9 centimeters, body weight = 74.2 +/- 5.4 kilograms) and women (n = 4, height = 163.8 +/- 4.1 centimeters, weight = 58.8 +/- 4.8 kilograms). The Universal Gym bench press machine was used. Head ventroflexion was maintained by depression of the chin on a battery-operated module placed on the chest. Removal of chin contact emitted a buzzer sound, indicating an incorrect position. Dorsiflexion occurred by lowering the head below the surface of the bench. The neutral position was assumed with the head in contact with the bench. Hands were spaced shoulder-width apart. Two trials were taken at each head position, with the highest score examined. Power was the criterion score and was: P = f*d*t-1 (power in watts, force in kilograms, distance in meters, time in seconds). Movement time was recorded as the bar moved from the chest up to 0.25 meter. A 2 x 3 ANOVA with two levels of gender and three levels of head position disclosed that ventroflexion inhibited power for men (mean = 145.3 watts) relative to a neutral head position (mean = 181.5 watts) and dorsiflexion (mean = 171.2 watts). For women, both ventroflexion (mean = 62.4 watts) and neutral (mean = 63.9 watts) positions were significantly less than dorsiflexion (mean = 85.1 watts).

(C) 1991 National Strength and Conditioning Association