Effect of external and internal cues on core muscle activation during the Sahrmann five-level core stability test

BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of core muscle activation and a person's ability to stabilize the lumbopelvic complex.Preparatory cues and images can be used to increase the activation of these muscles.To attain optimal movement patterns,it will be necessary to determine what cueing will give the most effective results for core stability.AIM To investigate the effects of external and internal cues on core muscle activation during the Sahrmann five-level core stability test.METHODS Total 68 participants(21.83±3.47 years)were randomly allocated to an external(n=35)or internal cue group(n=33).Participants performed the Sahrmann fivelevel core stability test without a cue as baseline and the five-level stability exercises with an internal or external cue.External cue group received a pressure biofeedback unit(PBU),and the internal cue group received an audio cue.A Delsys Trigno^(TM)surface electromyography unit was used for muscle activation from the rectus abdominis,external oblique,and transverse abdominis/internal oblique muscles.RESULTS Linear mixed effects model analysis showed that cueing had a significant effect on core muscle activation(P=0.001);however,there was no significant difference between cue types(internal or external)(P=0.130).CONCLUSION Both external and internal cueing have significant effects on core muscle activation during the Sahrmann five-level core stability test and the PBU does not create higher muscle activation than internal cueing.

Empirical Analysis on Factors Affecting Mobile Internet Users’ Purchase Intention for 3G Handsets

The research on consumers' purchase intention for 3G handsets has important theoretical and practical value. This research puts forward four key factors which influence consumers' purchase intention based on the cue utilization theory, situational theory and social impact theory, then it establishes the study model for consumers' purchase intention of 3G handsets. Based on the result of the questionnaire survey and empirical analysis, the study shows that social influence is the most prominent factor in purchase intention. Moreover, as different from results of previous studies, the situational influence factors have no significant impact on purchase intention in the 3G handsets market. The results of the model provides a forceful evidence for operators' and handset manufacturers' decision-making of 3G handsets design and marketing strategies, and it will improve their social impact.