ORIGINAL ARTICLE Quantifying competitive swim training using accelerometer-based activity monitors Brian V. Wright • Joel M. Stager Published online: 3 July 2013 Ó International Sports Engineering Association 2013 Abstract Recent advances in miniaturized waterproof accelerometers have allowed their use as a tool in exam- ining swim stroke characteristics (Ohgi et al. JPSE Int J 45:960–966, 2002; Sports Eng 6:113–123, 2003). A better use for this technology, however, might be to quantify characteristics of competitive swim training. The purpose of this study was thus to examine commercial accelerom- eters’ ability to track and quantify swim training variables common to all swim training programs: speed and distance. Swimmers (n = 43) were fitted with two accelerometer monitors on their right wrist and ankle. From this output, regression analyses were performed as a means to describe swim distance and speed. Ten additional swimmers (experimental group, n = 10) were then utilized to cross validate these equations as being useful to predict swim distance and speed. The results demonstrated a positive, significant relationship between activity counts and actual swim distance (r = 0.90, p \ 0.05), actual swim speed (r = 0.80; p \ 0.05), and cross validation confirmed the accuracy of the prediction equations. The findings of the present study suggest that commercial accelerometer-based activity monitors have the ability to quantify important characteristics of competitive swim training. Keywords Accelerometer-based activity monitor Á Competitive swimming Á Swim training 1 Introduction Interval training is widely used by competitive swim coa- ches as a means to initiate improvements in swim perfor- mance [1–4]. Typically, interval training employs various repeated swim bouts at given distances, intensities and durations. Prescribed rest intervals are included between bouts to purposely permit partial, but not complete recov- ery [2]. A modern competitive training season therefore is a series of complex, prescribed work bouts that require continual instruction and constant feedback between the swimmers and coaches. To achieve the ultimate goal (i.e., continual improvements in swim performances), coaches prescribe what they perceive as the appropriate training stimulus, and the swimmers presumably comply with this. However, the coach must (1) assume his or her athletes comply with the prescribed training and (2) be able to determine whether or not the athletes are responding appropriately to the prescribed training. Coaches to do their jobs, therefore, must continually monitor and record their athletes’ daily training and swim performances. Currently, little technology is commercially available for use by coaches beyond a simple handheld stopwatch or wall- mounted pace clocks. To complicate this further, coaches regularly oversee multiple athletes (from 10 to 50 swimmers) simultaneously during an ordinary training session. To this is the added challenge of monitoring athletes who are concurrently completing different workout plans. Thus, due to these difficulties, it is nearly impossible for competitive swim coaches to effectively quantify and monitor such standard B. V. Wright (&) Department of Exercise Sport Science, Austin College, 900 N. Grand Ave, ste. 6A, Sherman, TX 75090, USA e-mail: bwright@austincollege.edu J. M. Stager Counsilman Center for the Science of Swimming, Indiana University, HPER Building 104 E. 7th Street, Bloomington, IN 47405, USA e-mail: stagerj@indiana.edu Sports Eng (2013) 16:155–164 DOI 10.1007/s12283-013-0123-1