The Traction Reaction in Infancy - Clinical and Electromyographic Study of Normal Infants

Abstract

The traction reaction was studied in 23 normal infants on 45 occasions at ages ranging from 2 weeks to 12 months. The distribution of the developmental phases of the reaction to some extent differed from that expected from age according to the description of Vojta (1976). EMG recordings from 15 trunk and leg muscles were obtained on 37 occasions from 20 of the infants. Six types of EMG activation pattern during traction were observed in different overlapping age periods from 1 month to 12 months. From these patterns, four well separated stages of motor development were distinguished. They were as follows:
1) No EMG activity related to traction.
2) Trunk flexor activation with weak or irregular activation in leg muscles.
3) Reciprocal activation in trunk flexor and extensor muscles combined with strong co-activation of the leg muscles, and
4) Trunk muscles activated as in stage 3, but the coactivation in leg muscles abolished and gradually followed by functionally adequate activation in some of the leg muscles.

Key words

Traction reaction - Development phases - Normal infants - Electromyography