Pain intensity and muscle tension
Pain intensity and muscle tension were assessed using sepa- rate 10-cm visual analogue scales (VAS). The intensity of pain and feeling of muscle tension were reported by the partici- pants using numerical analog scales ranging from 0 to 10 on which 0 indicated no pain or no muscle tension, respectively, and 10 indicated the most pain ever and the tensest ever experienced. Reliability of data obtained with these VAS is reported to be high (r Z 0.99) (Scott and Huskisson, 1979), with high construct validity (Wilkie et al., 1990).