Can the Use of Unstable Surfaces and Instruction for Conscious Abdominal Contraction Increase the EMG Activity of the Periscapular Muscles During the Dynamic Push-Up?

Abstract

Context: It is believed that conscious abdominal contraction (CAC) during exercise encourages greater periscapular activation through existing myofascial connections. On the other hand, it is postulated that the use of unstable surfaces would promote greater neuromuscular demand. Objective: To analyze the effect of CAC on periscapular muscle activity during push-up plus exercise on stable and unstable surfaces and to evaluate the correlation between electromyographic (EMG) activity of the serratus anterior (SA) and abdominal oblique muscles. Design: Repeated-measures design in a single group, pre–post CAC. Setting: Biomechanics laboratory. Participants: Twenty-three male volunteers without a history of lesions in the upper limbs participated in the study. Main Outcome Measures: Five repetitions of push-ups on stable and unstable surfaces were performed with and without instruction for CAC. The normalized amplitude of the EMG activity was obtained from the muscles of the upper, middle, and lower trapezius, SA upper (SA_5th) and lower (SA_7th) portions, external oblique (EO), and internal oblique. Results: CAC increased the activity of the EO, internal oblique, middle trapezius, and SA (P < .05) in both surfaces. The use of the unstable surface increased the EMG activity of the EO, SA_7th, and middle trapezius and decreased the EMG activity of the SA_5th. However, all changes observed in EMG signals were of low magnitude, with effect sizes lower than 0.45. There was a weak correlation between the EMG activity of the EO and SA_5th (r = .24) and a strong correlation between the EO and SA_7th (r = .70). Conclusion: The isolated use of CAC or unstable surface during push-up seems to present no practical relevance, but the combined use of these strategies may increase activation of the SA_7th and middle trapezius muscles.

Electromyographic analysis of the serratus anterior and upper trapezius in closed kinetic chain exercises performed on different unstable support surfaces: a systematic review and meta-analysis

“…Regarding external validity, eight studies included a representative sample of men and women ( Tucker et al, 2010 ; Maenhout et al, 2010 ; De Mey et al, 2014 ; Byrne et al, 2014 ; Herrington, Waterman & Smith, 2015 ; Youdas et al, 2018 ; Youdas et al, 2020a ; Biscarini, Contemori & Grolla, 2019 ) and only two reported dropouts throughout the study ( Byrne et al, 2014 ; Patselas et al, 2021 ). Regarding internal validity, ten of the included articles ( Martins et al, 2008 ; Tucker et al, 2010 ; De Araújo et al, 2011 ; De Araújo et al, 2018 ; De Araújo et al, 2020 ; Park et al, 2013 ; Kim et al, 2014 ; Pirauá et al, 2014 ; Karagiannakis, Athanasopoulos & Mandalidis, 2018 ; De Faria et al, 2021 ) carried out a physical evaluation of the participants to identify any clinical condition. In addition, only three studies ( Lee, Lee & Park, 2013 ; De Araújo et al, 2018 ; Biscarini, Contemori & Grolla, 2019 ) standardized movement velocity and phase duration of the exercises, and all of them included direct observation of participants during testing procedure.…”

“…Only four articles ( Lehman, Gilas & Patel, 2008 ; Seo et al, 2013 ; De Mey et al, 2014 ; Herrington, Waterman & Smith, 2015 ) did not report the randomization of the exercises or support surface type. All the articles presented an appropriate normalization of the EMG signal, nevertheless only five studies ( Pirauá et al, 2014 ; Horsak et al, 2017 ; De Araújo et al, 2018 ; De Araújo et al, 2020 ; De Faria et al, 2021 ) randomized MVIC measurement, and one study ( Park et al, 2013 ) did not specify the statistical test performed for multifactorial analysis, only describing the pair comparison test. Lastly, four studies ( Martins et al, 2008 ; Gioftsos et al, 2016 ; Horsak et al, 2017 ; Patselas et al, 2021 ) included trial to trial reliability analysis among EMG measurements.…”

Shoulder electromyography activity during push-up variations: a scoping review

“…Six PU variations met inclusion criteria and included: standard PU (n ¼ 17), 7,9,13,14,[18][19][20][21][22][23][24][25][26][27][28][29][30] PU plus (n ¼ 11), 11,12,18,20,29,[31][32][33][34][35][36] suspension system (n ¼ 7), 10,13,14,24,27,30,37 , hands on an unstable surface (n ¼ 6), 7,13,18,21,22,29 incline (n ¼ 3), 25,38,39 and incline with hands on an exercise ball (n ¼ 3). 25,38,39 Figures 1 and 3 provide representative images of these PU variations.…”

“…25,38,39 Figures 1 and 3 provide representative images of these PU variations. Five muscles met inclusion criteria, including: SA (n ¼ 17), 9,[11][12][13][18][19][20][21][22][23][24][28][29][30]34,35,38 UT (n ¼ 17), [10][11][12]14,18,19,[21][22][23]29,30,[32][33][34][36][37][38] pectoralis major (PM; n ¼ 13), 7,[10][11][12][24][25][26][27]30,31,34,37,39 middle and lower fibers ...…”

“…25,38,39 Figures 1 and 3 provide representative images of these PU variations. Five muscles met inclusion criteria, including: SA (n = 17), 9,11–13,18–24,28–30,34,35,38 UT (n = 17), 10–12,14,18,19,21–23,29,30,32–34,36–38 pectoralis major (PM; n = 13), 7,10–12,24–27,30,31,34,37,39 middle and lower fibers of trapezius (M/LT; n = 11), 11,12,18,20–23,28,29,35,38 and triceps brachii (n = 11). 7,10,…”