Case report  CARDIOVASCULAR SYSTEM 

The Journal of Sports Medicine and Physical Fitness 2004 December;44(4):428-35

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Development of the Muscle Dysmorphia Inventory (MDI)

Rhea D. J. ¹, Lantz C. D. ², Cornelius A. E. ³

¹ Department of Kinesiology Texas Christian University, Ft. Worth, TX, USA 2 Truman State University, Kirksville, MO, USA 3 Springfield College, Springfield, IL, USA

Aim. The devel­op­ment of the 6-­factor, 27-­item ­Muscle Dys­mor­phia Inven­tory (MDI) was ­based on ­Lantz et al. pro­posed ­model of char­ac­ter­is­tics asso­ciated ­with ­Muscle Dys­mor­phia.
­Methods. Experi­mental ­design: quan­ti­ta­tive pro­ce­dures ­including ­item-to-­total cor­re­la­tions, explor­a­tory and con­fir­ma­tory ­factor anal­yses, and struc­ture equa­tion mod­eling con­firmed the con­struct ­validity of the ­scale. Con­ver­gent ­validity was ­also ­tested. Set­ting: body­building and pow­er­lifting com­pe­ti­tion ­venues, ­weight ­training facil­ities, and uni­ver­sity ath­letic ­venues. Par­tic­i­pants: the 1st ­study con­sisted of 77 expe­ri­enced ­male ­free ­weight ­lifters. The 2nd ­study con­sisted of 156 ­male non-com­pet­i­tive body­builders and ­weight ­lifters and 168 ­elite ­level pow­er­lifters and body­builders. The 3rd ­study con­sisted of 151 ­male and ­female body­builders and ­weight ­lifters. Meas­ures: ­each par­tic­ipant com­pleted dem­o­graphic infor­ma­tion, the ­MDI, ­Drive for Thin­ness sub­scale of the ­Eating Dis­order Inven­tory, and the ­Training Depen­dency sub­scale of the Body­building Depen­dence ­Scale.
­Results. ­Reliability esti­mates (­Cronbach’s α) ­ranged ­from 0.72 to 0.94. ­Factor load­ings in all 3 ­studies sup­ported the 6-­factor struc­ture (­size/symm­etry, sup­ple­ment use, exer­cise depen­dence, phar­mac­o­log­ical use, die­tary ­behavior, and phy­sique pro­tec­tion). ­Much of the ­scale val­i­da­tion was ­focused on con­struct ­validity, how­ever, cor­re­la­tions ­with the ­MDI’s sub­scales and the ­Training Depen­dency sub­scale of the Body­building Depen­dence ­Scale and the ­Drive for Thin­ness sub­scale of the ­Eating Dis­order Inven­tory pro­vided evi­dence of con­ver­gent ­validity ­also.
Con­clu­sion. ­From ­these pre­lim­i­nary ­results, the MDI ­appears to con­tribute to the iden­tifi­ca­tion of a ­newly ­formed dis­order by ­offering a ­multi-dimen­sional ­measure of fac­tors ­related to Muscle Dys­mor­phia.