title: The Effects of Either a Mirror, Internal or External Focus Instructions on Single and Multi-Joint Tasks.
abstract: Training in front of mirrors is common, yet little is known about how the use of mirrors effects muscle force production. Accordingly, we investigated how performing in front of a mirror influences performance in single and multi-joint tasks, and compared the mirror condition to the established performance effects of internal focus (IF) and external focus (EF) instructions in a two part experiment. In the single-joint experiment 28 resistance-trained participants (14 males and 14 females) completed two elbow flexion maximal voluntary isometric contractions under four conditions: mirror, IF, EF and neutral instructions. During these trials, surface EMG activity of the biceps and triceps were recorded. In the multi-joint experiment the same participants performed counter-movement jumps on a force plate under the same four conditions. Single-joint experiment: EF led to greater normalized force production compared to all conditions (P≤0.02, effect-size range [ES] = 0.46-1.31). No differences were observed between neutral and mirror conditions (P = 0.15, ES = 0.15), but both were greater than IF (P<0.01, ES = 0.79-1.84). Surface EMG activity was comparable across conditions (P≥0.1, ES = 0.10-0.21). Multi-joint experiment: Despite no statistical difference (P = 0.10), a moderate effect size was observed for jump height whereby EF was greater than IF (ES = 0.51). No differences were observed between neutral and mirror conditions (ES = 0.01), but both were greater than IF (ES = 0.20-22). The mirror condition led to superior performance compared to IF, inferior performance compared to EF, and was equal to a neutral condition in both tasks. These results provide novel and practical evidence concerning mirror training during resistance type training.
authors.affiliation: Physiology Discipline, Australian Institute of Sport, Canberra, Australian Capital Territory, Australia.|Centre for Exercise and Sport Science Research, School of Medical & Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
authors.forename: Israel
authors.initials: I
authors.lastname: Halperin
authors.affiliation: Physiology Discipline, Australian Institute of Sport, Canberra, Australian Capital Territory, Australia.|Centre for Exercise and Sport Science Research, School of Medical & Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
authors.forename: Steven
authors.initials: S
authors.lastname: Hughes
authors.affiliation: Institute of Sport, Exercise & Active Living, College of Sport & Exercise Science, Victoria University, Footscray, Victoria, Australia.|Skill Acquisition Discipline, Australian Institute of Sport, Canberra, Australian Capital Territory, Australia.
authors.forename: Derek
authors.initials: D
authors.lastname: Panchuk
authors.affiliation: Centre for Exercise and Sport Science Research, School of Medical & Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Abbiss
authors.affiliation: Physiology Discipline, Australian Institute of Sport, Canberra, Australian Capital Territory, Australia.|Centre for Exercise and Sport Science Research, School of Medical & Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
authors.forename: Dale W
authors.initials: DW
authors.lastname: Chapman
mesh_terms: D000328:Adult; D001288:Attention; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D007596:Joints / Q000502:physiology*; D008297:Male; D009132:Muscles / Q000502:physiology*