medicina Article Comparison of Lateral Abdominal Musculature Activation during Expiration with an Expiratory Flow Control Device Versus the Abdominal Drawing-in Maneuver in Healthy Women: A Cross-Sectional Observational Pilot Study Vanesa Abuín-Porras 1 , Paula Maldonado-Tello 1,Mónica de la Cueva-Reguera 1, David Rodríguez-Sanz 2 ,César Calvo-Lobo 2 , Daniel López-López 3 , Emmanuel Navarro-Flores 4 and Carlos Romero-Morales 1,* 1 Faculty of Sport Sciences, Universidad Europea de Madrid, Villaviciosa de Odón, 28670 Madrid, Spain; [email protected] (V.A.-P.); [email protected] (P.M.-T.); [email protected] (M.d.l.C.-R.) 2 Facultad de Enfermería, Fisioterapia y Podología, Universidad Complutense de Madrid, 28040 Madrid, Spain; [email protected] (D.R.-S.); [email protected] (C.C.-L.) 3 Research, Health and Podiatry Group, Department of Health Sciences, Faculty of Nursing and Podiatry, Universidade da Coruña. La Coruña, 15403 Ferrol, Spain; [email protected] 4 Department of Nursing, Faculty of Nursing and Podiatry, Frailty and Cognitive Impairment Organized Group (FROG). University of Valencia, 46001 Valencia, Spain; manu.navarrofl[email protected] * Correspondence: [email protected]; Tel.: +34-912-115-268 Received: 2 February 2020; Accepted: 15 February 2020; Published: 19 February 2020 Abstract: Background and Objectives: The purpose of the present study was to quantify and compare lateral abdominal musculature thickness, including the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles, via rehabilitative ultrasound imaging (RUSI) during the use of the expiratory flow control device (EFCD) versus the classic abdominal drawing-in maneuver (ADIM). Materials and Methods: A cross-sectional observational pilot study. Twenty-one women were recruited and assessed the thickness of each muscle (TrA, IO, and EO) by ultrasound imaging at rest, during the ADIM, and during expiration with the EFCD. Waist circumference was also measured under the same circumstances. Results: Statistically significant differences were observed between ADIM, EFCD, and at rest condition for the thickness of the TrA (p = 0.001) and IO (p = 0.039). Moreover, statistically significant differences for TrAb at rest compared with the ADIM (p = 0.001, Cohen’s d = 2.183) and at rest and with the EFCD (p = 0.001, Cohen’s d = 2.843). In addition, between ADIM and EFCD were not statistically significant, although a moderate effect size was found (p = 0.055, Cohen’s d = 0.694). For the IO muscle thickness, significant differences were reported between the EFCD and at rest (p = 0.038), Cohen’s d = 0.081). Conclusions: Significant differences in the increase of the thickness of the TrA and IO muscles during the use of the EFCD and the ADIM with respect to rest. In addition, for the TrA, statistically significant differences were found during expiration with the EFCD with respect to the ADIM. Expiration with EFCD can be a useful method for the activation of the TrA. Keywords: ultrasonography; abdominal muscles; abdominal drawing-in maneuver; muscle activity Medicina 2020, 56, 84; doi:10.3390/medicina56020084 www.mdpi.com/journal/medicina Medicina 2020, 56, 84 2 of 9 1. Introduction The lateral musculature of the abdomen comprises, from deep to superficial, the transverse Medicinaabdominis 2020, (TrA), 56, x FOR internal PEER REVIEW oblique (IO), and external oblique (EO) muscles [1]. 2 of 9 The TrA is a part of the deep stabilization system of the trunk, along with the multifidus, the diaphragm,The TrA and is a the part pelvic of the floor deep musculature stabilization [ 2system–4]. These of the muscle trunk, activations along with cause the multifidus, an increase the of ditheaphragm intra-abdominal, and the pelvic pressure, floor contributing musculature to [2 lumbopelvic–4]. These muscle stabilization activation [5s]. cause In patients an increase with lowerof the intraback-abdominal pain, there pressure, is a change contributing in abdominal to lumbopelvic muscle recruitment stabilization during [5]. activitiesIn patients demanding with lower trunk back pain,stability there [6– is8]. a Thechange TrA in can abdominal also be considered muscle recruitment the most powerfulduring activities musculature demanding during trunk expiration stability by [6increasing–8]. The TrA abdominal can also pressurebe considered and pushing the most the powerful diaphragm musculature towards during the thorax, expiration especially by increasing in forced abdominalexpiration [pressure6]. There and is also pushing a close the relationship diaphragm between towards the the musculature thorax, especially of the in pelvic forced floor expiration and the [6]abdominal. There is musculature also a close [relationship7]. 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[11 Due,12] to, improvingthe difficulty pulmonary of the ADIM function execution, [13], and several in the authors reduction have of explored lumbar thepain TrA symptoms muscle activation[14]. Due to using the difficultythe expiratory of the muscleADIM execution, recruitment several and finding authors benefits have explored with respect the TrA to muscle the execution activation of anusing ADIM, the expiratoryin the increase muscle of therecruitment thickness and of thefinding TrA whenbenefits performing with respect maximal to the execution expiration of [13 an– 15ADIM,]. To guidein the increasethis expiratory of the flow,thickness an exsu of thefflation TrA nozzlewhen wasperforming developed maximal and tested expiration in urinary [13–15 incontinence]. To guide [this16], expiratoryan instrument flow, for an performing exsufflation active nozzle expiration was developed through and an 8-mmtested tube, in urinary which incont maintainsinence the [16] glottis, an instrumentopen. The expiratoryfor performing flow active control expiration device (EFCD)—Winner through an 8-mm Flow tube,® whichversion. maintains 2.0 (Prim the Fisioterapia glottis open. y TheRehabilitaci expiratoón,ry Madrid,flow control Spain) (Figuredevice 1(EFCD))—is an— evolutionWinner ofFlow this® firstversion model. 2.0 [ 16 (],Prim and wasFisioterapia developed y Rehabilitaciónto redirect pressure,, Madrid and, Spain) based on(Figure abdominal-perineal 1)—is an evolution synergy of this and first the model expiratory [16], and function was developed of the TrA, toan redirect adjustable pressure, increase and in expiratorybased on abdominal flow may be-perineal generated synergy [17]. and the expiratory function of the TrA, an adjustable increase in expiratory flow may be generated [17]. FigureFigure 1. ExpiratoryExpiratory Flow Flow Control Control Device Device ( (EFCD)EFCD) (Winner (Winner Flow, v2.0). Rehabilitative ultrasound imaging (RUSI), commonly used for the study of muscle morphology morphology and characteristics,characteristics, hashas been been shown shown as as a techniquea technique which which presents presents good good reliability reliability with with regard regard to trunk to trunkstabilizers stabilizers [18]. The [18] validity. The ofvali ultrasounddity of ultrasound measurements measurements of this musculature of this hasmusculature been compared has been with comparedmeasurements with using measurements magnetic resonance using imaging magnetic (MRI), resonance obtaining animaging intercorrelation (MRI), coeobtainingfficient (ICC) an intercorrelationbetween 0.78 and coefficient 0.95 [3]. Moreover, (ICC) between RUSI can0.78 detect and 0.95 changes [3]. inMoreover, TrA and IORUSI activity can detect related changes to changes in TrAin their and thickness IO activ [ity19 ].related In addition, to changes the use in oftheir ultrasound thickness to assess[19]. In the addition, changes the produced use of ultrasound in the TrA, IO,to assessand EO the during changes an ADIMproduced [3,19 in,20 the] and TrA, during IO, and maximal EO during expiration an ADIM [9,21 [3,19,] has20] been and validated. during maximal expirationIn this [9,21] study, has RUSI been was validated. used to compare lateral abdominal musculature thickness using ADIM versusIn athis forced study, expiration RUSI was through used to thecompa EFCDre lateral with theabdominal