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.

Acute and Long-Term Effects of Attentional Focus Strategies on Muscular Strength: A Meta-Analysis

“…Therefore, 28 full-text papers were read. Nineteen studies were excluded after reading the full texts, and a total of nine studies were included in the review [13][14][15][16][25][26][27][28][29]. There were 555 search results in the secondary searches, and one additional study was included in the review [30].…”

Superiority of external attentional focus for motor performance and learning: Systematic reviews and meta-analyses.

“…We describe several studies of brain-related neurophysiological activity associated with different attentional foci, but this area of the literature is nascent and not yet amenable to meta-analytic evaluation. A body of work, nevertheless, has assessed muscular (EMG) activity under EF and IF conditions for tasks involving maximal or submaximal force production (e.g., Greig & Marchant, 2014; Halperin, Hughes et al, 2016; Lohse & Sherwood, 2012; Vance et al, 2004), basketball free-throw shooting (Zachry et al, 2005), or dart throwing (Lohse et al, 2010). We examined EMG activity only in the context of significant behavioral effects of attentional focus.…”

Effects of mirror feedback during balanced exercise performance in the old people with mild cognitive impairment

“…Mirror was not utilized for the first nonmirror feedback trial. As for the second mirror feedback trial, procedure was conducted as reported by previous study (Halperin et al, 2016). A full-body sized mirror was placed 1 m away from the subject for a full-body observation by the subjects.…”

“…Utilizing a mirror for providing information for proper movement during various physical activities has long been recommended. Despite of its popularity in various fitness settings, there have been mixed reports on the advantageous nature of the mirror on the motor performance (Halperin et al, 2016). For example, a study which observed balance exercise in the old people did not show considerable improvement in balance (Vaillant et al, 2004).…”