Both weightlifting belts and wrist straps are commonly used weightlifting training aids but their effects on deadlift kinematics and performance were still not known. This study examined the effects of weightlifting belts and wrist straps on the kinematics of the deadlift exercise, time to complete a deadlift and rating of perceived exertion (RPE) in male recreational weightlifters Men Lever Belt Gym.
This study used a repeated-measures, within-subjects design. Twenty male healthy recreational weightlifters (mean age ± standard deviation = 23.1 ± 2.5 years) were recruited from 2 local gyms and the Education University of Hong Kong between January and April 2021. All participants used various combinations of belt and straps during a conventional deadlift. The hip and knee flexion, cervical lordosis, thoracic kyphosis and lumbar lordosis angles and time to complete a deadlift were measured using video analysis software. RPE was also recorded.
Wearing both a belt and wrist straps was found to reduce knee flexion angle (P < .001), but not hip flexion angle (P > .05), during the setup phase of the deadlift compared to wearing no aid. Wearing straps alone exaggerated thoracic kyphosis in the lockout phase of the deadlift compared to wearing a belt alone (P < .001). No changes were seen in cervical and lumbar lordosis angles when using any or both of the weightlifting aids. Additionally, the participants completed deadlifts faster when wearing both a belt and straps (P = .008) and perceived less exertion when wearing a belt and/or straps (P < .001).
Weightlifting belts and wrist straps, when using together, have positive effects on the kinematics of deadlift, time to complete a deadlift and RPE in male recreational weightlifters. Trainers should recommend the use of a belt and straps together, but not straps alone, to recreational weightlifters when performing deadlift training.
Keywords: equipment and supplies and biomechanical phenomena, lifting, sports
The deadlift is 1 of the 3 events performed in powerlifting competitions and is an exercise commonly prescribed for athletes to improve total body strength. However, lower back injury is very common among less-skilled recreational weightlifters as they tend to adopt a more stooped posture in the initial stages of the deadlift, leading to an elongated lever arm and placing more stress on the lower back.[1,2] It is widely acknowledged that use of a weightlifting belt can increase intra-abdominal pressure, stabilize the spine, decrease spinal compression and reduce the likelihood of spinal injuries during weightlifting training.[3–5] However, to the best of our knowledge, no study has investigated whether the use of a weightlifting belt can prevent the development of a stooped posture in recreational weightlifters in the initial stages of a deadlift. Moreover, no study has investigated whether the use of a weightlifting belt can alter the spinal curvature adopted in the finishing position of a deadlift, despite some evidence suggesting that it can prevent spinal shrinkage and affect lumbar spine kinematics during heavy lifting. This is important as spinal curvature affects the stress placed on the facet joints and intervertebral discs, thereby altering the overall compressive strength experienced by the spine. It has been hypothesized that use of weightlifting belts may reduce spinal curvature and thus exert a protective effect against spinal injuries.
Many studies have reported that weightlifters experienced a greater sense of support and believed that their lifting capacity increased when wearing a belt.[3,9] As such, we hypothesized that weightlifters may perceive less exertion and altered lifting velocity when wearing a belt. The first aim of this study was therefore to investigate the effects of using a weightlifting belt on lower limb joint angles in the initial stages of a deadlift, spinal curvatures adopted in the finishing position, overall rating of perceived exertion (RPE) and total time to complete a deadlift in recreational weightlifters.
Another commonly used weightlifting training aid is a pair of wrist straps. Strap use can enhance grip strength and may provide a psychological boost when lifting heavy weights.[12–14] However, such straps attach the weightlifter directly to the loaded bar and may thus alter lifting kinematics and have the potential to injure the athlete if not used safely. To date, no studies have investigated the influence of using wrist straps on weightlifting kinematics. However, previous studies have revealed that using lifting straps during deadlift training could result in slower movement speed and decreased perceived exertion. Therefore, the second aim of this study was to investigate the effects of using wrist straps on lower limb joint angles and spinal curvatures during a deadlift, overall RPE and total time to complete a deadlift in recreational weightlifters. We hypothesized that using wrist straps may alter lower limb joint kinematics and spinal curvatures, reduce overall RPE and increase time to complete a deadlift. As both weightlifting belts and wrist straps may be used together, the third aim of this study was to examine the effect of these aids when used together. Our results could inform the use of weightlifting belt and wrist straps in recreational weightlifters.
This study used a repeated-measures, within-subjects design. Following a warm-up (described in Beckham et al), all participants underwent weightlifting assessments with and without using a belt and/or wrist straps (condition 1: belt and straps; condition 2: belt alone; condition 3: straps alone; and condition 4: no belt and no straps) during a conventional deadlift with a loaded barbell. Measurements included hip and knee flexion angles in the starting position of a conventional deadlift and cervical lordosis, thoracic kyphosis and lumbar lordosis angles in the finishing position, in addition to the total time taken to complete a conventional deadlift and self-reported RPE. The order of testing conditions was randomized, and all tests were performed within 1 day.
From January to April 2021, a sample of weightlifters were recruited from 2 local gyms and the Education University of Hong Kong through social media advertising and personal invitations. The inclusion criteria were men aged 18 to 30 years who have more than 3 years of weightlifting experience, have been training at least 4 hours per week, and engage in recreational weightlifting. The exclusion criteria were men with musculoskeletal disorders (e.g., leg length discrepancies and severe flat feet), neurological disorders (e.g., epilepsy), spinal problems (e.g., scoliosis), upper limb problems (e.g., history of shoulder dislocation, tennis or golf elbow) or recent injuries that could affect performance or who train regularly for other sports. Participants were asked to refrain from any type of exhausting activity for 48 hours prior to data collection to avoid muscle fatigue. The study was approved by the Human Research Ethics Committee (Department of Health and Physical Education) of the Education University of Hong Kong on November 19, 2020. Informed written consent was obtained from each participant prior to data collection. All procedures were performed according to the Declaration of Helsinki.
Basic demographic information and information regarding weightlifting experience were collected by interview. Body weight and height were measured, and body mass index was calculated. Handgrip strength of both hands and the conventional deadlift one-repetition maximum (1RM) of each participant were measured using a handgrip dynamometer and a loaded barbell, respectively. For the deadlift 1RM test the use of supportive aids was not permitted, but the use of chalk was allowed. The 1RM test protocol included a warm-up, loading increments and rest periods according to a previously established protocol. Procedures followed during the 1RM test were as described below. The participants were given a 30-minute recovery period following the 1RM test prior to experimental data collection.
Data collection was performed in the Physical Fitness Room of the Education University of Hong Kong or a local gymnasium by 3 student researchers with personal trainer or weightlifting coaching qualifications. Blinding of assessors were not feasible given the nature of the interventions (wearing different weightlifting devices). The participants wore a weightlifting belt (Heavywear Nylon Contour Belt H9, NC) for the “with weightlifting belt” conditions and/or put on a pair of wrist straps (Versa Gripps Professional Series, Versa Gripps, ME) for the “with wrist strap” conditions. The steps involved in completing a conventional deadlift have been detailed in Holmes. In brief, during the setup phase (assuming the starting position), the participants stood with feet flat placed between hip- and shoulder-width apart, with toes pointing slightly outward. With a slight flexion in both knees, the participants bent down toward the bar and let the hips move backward. They grasped the bar with a double overhand grip, placing their hands slightly wider than shoulder-width apart, with both elbows fully extended. The participants then lowered their hips further until their shins touched the bar. They were reminded to keep their back flat to maintain a neutral spine (Fig. 1A). During the upward phase, the participants lifted the bar by extending the hips and knees until the body reached an upright standing position (lockout or finishing position) (Fig. 1B). During the lowering phase, the participants kept their back flat and bent their hips and knees to lower the bar to the floor. A spotter stood in front of each participant to ensure safety and instruct the participants to perform the lift at a comfortable speed without the use of Valsalva maneuver. The participants performed 1 deadlift repetition at 80% of their 1RM for each testing condition. The rest interval between testing conditions was 3 minutes.
Angle definitions. (A) Hip and knee joint flexion angles in the setup phase and (B) cervical lordosis, thoracic kyphosis, and lumbar lordosis angles in the lockout phase of a deadlift.
A video camera was used to record the deadlift movement in the sagittal plane. The Coach My Video software (CoachMyVideo, USA) (www.coachmyvideo.mobi) was used to extract kinematic data (primary outcomes) from these video clips. The test-retest reliability of this software was found to be good (intraclass correlation coefficient ranged from 0.7-0.8) in our pilot trial and the validity of this kind of motion analysis application has been reported to be excellent. The kinematic data extraction method was based on Gong et al and is described below. During the setup phase, hip flexion describes the angle between the trunk and thigh, whereas knee flexion is the angle between the thigh and shank. Smaller values represent a greater range of motion or a deeper squat (Fig. 1A). Cervical lordosis describes the angle formed between the head and neck. Similarly, thoracic kyphosis describes the angle between the neck and trunk. Lumbar lordosis describes the angle between trunk and hip. In these cases, smaller values represent increased lordosis/kyphosis (Fig. 1B). All kinematic data extraction was based on fixed bony landmarks and with reference to goniometric measurement of joint angles. Additionally, the total time required to complete a deadlift (i.e., timed from the moment the bar was lifted off the floor to the moment the bar was placed on the floor again, a secondary outcome measure) was recorded. A shorter completion time indicates greater explosive power. After each testing condition, the participants were asked to quantify their overall perceived exertion on a modified RPE scale (another secondary outcome measure). The scale ranged from 0 (resting) to 10 (maximal), with lower scores indicating less perceived exertion.
