Anthropometrical Determinants of Deadlift Variant Performance.

Author:Cholewa, Jason M.
 
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Introduction

The barbell deadlift is a popular exercise employed to increase the strength of the posterior kinetic chain in athletes, recreational weight lifters, and the elderly, and is also one the three lifts tested during competitive powerlifting. The barbell deadlift is performed with two different styles in powerlifting competitions: conventional deadlift (CDL) and sumo deadlift (SDL). The CDL requires the lifter to stand with feet approximately hip width apart, flex at the hips slightly more than at the knees, grasp the bar just outside the knees, and then lift the bar to standing using the hip and knee extensors. The SDL, on the other hand, requires the lifter to stand with the feet wider than shoulder width apart, bend equally at the knees and hips, grasp the bar inside the knees, and then lift the bar to a standing position using the hip and knee extensors (Belcher, 2017).

Several studies have demonstrated that body height, arm and leg lengths may influence how an individual performs a CDL (Hales, 2010; Mayhew et al., 1993). Further-more, anecdotal evidence has suggested that individuals with a longer arm length and limb length relative to height may be more efficient at deadlifting (Lockie et al., 2018b; Mayhew et al., 1993). In contrast, Mayhew et al. (1993) ( found that shorter limb lengths had a positive effect on the CDL when performed by collegiate football players; however, full anthropometrical profiles were not reported. To the best of the authors' knowledge, only one study has examined the relationship between body structure and deadlifting performance (Lockie et al., 2018b). Lockie et al. (2018b) investigated the relationship between anthropometric profile (height, arm length and leg length) and CDL as well as high-handle hexagonal bar deadlift (HDL) performance. In men, only leg length correlated positively with absolute, but not relative 1RM CDL strength, suggesting that longer-legged men can deadlift more weight but do not have a biomechanical advantage relative to body mass. Secondly, height correlated negatively with relative, but not absolute HDL strength, suggesting taller men have a biomechanical disadvantage in the HDL relative to body mass regardless of relative leg or arm length. In women, no anthropometric variable correlated with any measure of absolute deadlift strength in either variation and no variable correlated with any absolute or relative strength measurement in the HDL. In contrast, for the CDL, height, leg length and arm length all negatively correlated with relative strength, but the ratio of arm-to-leg length did not, suggesting it is biomechanically beneficial for women to be short and have short limbs for CDL performance. In a second study, Lockie et al. (2018a) found individuals using the H DL had a signif ica ntl y hi ghe r 1 RM when co mp ared to th e CDL, likely attributable to a shorter lift distance and higher starting height, resulting in less total work required to lift the weight compared to the CDL.

Hales (2010) proposed that athletes with long arms should use the CDL and those with shorter arms would be better suited to use the SDL. From a biomechanical perspective, McGuigan and Wilson (1996) reported that the SDL offered a mechanical advantage over the CDL due to greater trunk extension and less torque at the lumbar spine, in addition to a shorter lift distance. Differences in muscle activation and biomechanics have been studied between the two styles with minimal differences in EMG activity in the lower limbs or hip extension range of motions reported in 3D analysis (Belcher, 2017; Camara et al., 2016), and informal conversations with competitive power lifters suggest a clear preference for one style over another. Nonetheless, to our knowledge, there is no research investigating the relationships between height and arm length and leg length between the CDL and SDL.

This is of importance to strength and conditioning coaches who are trying to find what style (e.g. sumo or conventional) may be most appropriate for athletes who are being introduced to the deadlift exercise, and holds implications in inexperienced powerlifters and recreational lifting community members who are trying to maximize their deadlift performance. Therefore, the purpose of this study was to investigate the interaction between limb and torso measurements and deadlift performance in the SDL and CDL in deadlift naive males and females. We hypothesized that greater performance in the CDL versus SDL would be positively correlated with longer relative arm and shorter relative femur lengths.

Methods

Deadlift naive subjects were recruited for this study to minimize a confounding effect of previous deadlift experience with a particular style on deadlift performance. Subjects were taught how to perform the conventional (CDL) and sumo deadlift (SDL) styles over the course of two training sessions. Anthropometric measurements included subject height, weight, upper arm, forearm, hand length, wrist and ankle girth, seated height, thigh length, and lower leg length. Subjects were then tested for counter movement vertical jump (CMJ) and abdominal crunch performance to investigate if a relationship between deadlift performance and the power to mass ratio (measured in proxy via the CMJ) or anterior core performance (measured via the abdominal crunch) existed. During the third and fourth sessions, subjects performed a 1 repetition maximum (1RM) test of either the CDL or SDL followed 5 minutes later by repetitions to fatigue of the corresponding style deadlift with 60% 1RM. The deadlift styles tested in session 3 and 4 were randomized (via coin flip). The anthropometrical variables were used to predict deadlift strength (see statistical procedures).

Participants

Participants were a convenience sample of 47 volunteers (n = 28 male, n = 19 female) recruited from a university population (Table 1). Subject inclusion criteria included being between the ages of 18-35 years old, without any reported musculoskeletal disorders, free from consumption of anabolic steroids or any other illegal agents known to increase muscle size within the past year, and were currently engaged in a structured resistance training program that did not involve deadlifting. Subjects were instructed to avoid taking any performance-enhancing supplements during the study period and avoid strenuous exercise two days prior to testing. All subjects gave their informed consent for inclusion before they participated in the study. The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Ethics...

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