Article

COMPARISON OF MUSCLE ACTIVATION AND KINEMATICS DURING THE DEADLIFT USING A DOUBLE‐PRONATED AND OVERHAND/UNDERHAND GRIP

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Abstract

This study examined muscle activation and relative joint angles during a conventional deadlift while using either a double‐pronated or overhand/underhand (OU) grip. Ten weight‐trained individuals performed the deadlift with 60% and 80% of their 1‐repetition maximum, with three different grip variations. EMG recordings were taken of the left and right biceps brachii, brachioradialis, upper trapezius, and upper latissimus dorsi. Motion capture was used to measure angles of the wrist, elbow, knee, and hip. With an OU grip, significant bilateral asymmetry was seen in EMG activity of biceps brachii and brachioradialis. Mean wrist and elbow angle also showed significant bilateral asymmetry when using an OU grip. Training recommendations for the OU grip deadlift should emphasize the need to vary which hand is supinated/pronated to avoid muscle imbalances and possible injury. Furthermore, it may be preferential to use a double‐pronated grip to avoid asymmetric training altogether.

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... It is critical for strength development (2,3) and is a primary component of powerlifting competitions, along with bench press and squat (8). Although high loads can be used in the deadlift, the lifter's ability to handle the bar, through grip strength, is often a limiting factor for the amount of weight that can be lifted (1,9). ...
... It has been previously suggested that training load has a fundamental role on maximum number of repetition performance and greater loads have been shown to optimize strength gains (13,24,28). Therefore, to enhance training loads and reduce fatigue of the forearm muscles during the deadlift exercise, many strategies have been suggested, such as the use of an inverted grip, alteration of bar thickness, magnesium powder, and use of lifting straps (1,20). The lifting straps are attached to the lifter's wrists and wrapped around the barbell or the handle of the resistance training equipment until fully tightened or secured (24). ...
... The higher HR values after the third deadlift set in the WS condition are likely related to increased cardiovascular demand as a result of the greater load applied compared with the NS condition (5). In addition, removing the limitation of grip strength likely allowed the ability to generate more work through larger muscles groups, subsequently increasing cardiac output (1,22). ...
... It is critical for strength development (2,3) and is a primary component of powerlifting competitions, along with bench press and squat (8). Although high loads can be used in the deadlift, the lifter's ability to handle the bar, through grip strength, is often a limiting factor for the amount of weight that can be lifted (1,9). ...
... It has been previously suggested that training load has a fundamental role on maximum number of repetition performance and greater loads have been shown to optimize strength gains (13,24,28). Therefore, to enhance training loads and reduce fatigue of the forearm muscles during the deadlift exercise, many strategies have been suggested, such as the use of an inverted grip, alteration of bar thickness, magnesium powder, and use of lifting straps (1,20). The lifting straps are attached to the lifter's wrists and wrapped around the barbell or the handle of the resistance training equipment until fully tightened or secured (24). ...
... The higher HR values after the third deadlift set in the WS condition are likely related to increased cardiovascular demand as a result of the greater load applied compared with the NS condition (5). In addition, removing the limitation of grip strength likely allowed the ability to generate more work through larger muscles groups, subsequently increasing cardiac output (1,22). ...
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Coswig, VS, Freitas, D, Gentil, P, Fukuda, DH, and Del Vecchio Boscolo, F. Kinematics and kinetics of multiple sets using lifting straps during deadlift training. J Strength Cond Res XX(X): 000–000, 2015—The deadlift is a fundamental exercise used in the development of whole body strength and a common element in resistance training programs for all levels. However, many practitioners report the fatigue of forearm muscles and possibly a lack of grip strength as obstacles to exercise performance, which may lead to the use of ergogenic aids, such as lifting straps. The objective of this study was to evaluate kinematic variables during the execution of multiple sets of deadlift with (WS) and without (NS) lifting straps. Eleven subjects (25 6 3.3 years) with an average of 4 6 2.6 years of resistance training experience were enrolled in the study. After the 1 repetition maximum (1RM) test WS and NS, subjects performed separate trials of 3 sets to failure at 90% of 1RM in a counterAU3 balanced fashion. With straps resulted in lower speed (0 to 225%) (23 to 210%) and greater force (20–28%) and duration (con: 0–13%) when compared with NS. Therefore, it is concluded that the use of straps directly influences exercise performance that requires manual grip strength, increasing the amount of work performed by the target muscles.
... To date, a study conducted by Beggs (2011) is the only existing study that investigated muscle activation through surface electromyography (EMG) of upper body muscles with different grip positions during a DL. However, the primary focus was placed on joint angles during the exercise, and thus, limited data was included regarding EMG. ...
... However, the primary focus was placed on joint angles during the exercise, and thus, limited data was included regarding EMG. Furthermore, Beggs (2011) only examined muscle activation of one forearm muscle (brachioradialis) when using two grips (MG and DOH) and two intensities (60% and 80% 1RM) and with no numeric data being provided in the results section regarding muscle activation, the practical significance of this study is limited. ...
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Muscle activation, peak velocity (PV) and perceived technical difficulty while using three grip variations and three loads during a deadlift exercise (DL) were examined. Twenty-nine resistance-trained athletes (15 males, age: 22.2±2.7 years; 14 females, age: 24.8±7.0 years) performed the DL with 50%, 70% and 90% of their one repetition maximum (1RM) using hook grip (HG), mixed grip (MG) and double overhand (DOH) grip. Surface electromyography (EMG) of the brachialis (BS), brachioradialis (BR) and flexor carpi ulnaris (FCU) was recorded. PV and perceived technical difficulty of each grip were also measured. Regardless of load and grip, females exhibited greater BS activation compared to males (p<0.05; ES=0.69) while males displayed greater BR activation, significant at 90% load (p<0.01; ES=1.01). MG elicited the least BR and FCU activation regardless of load and sex (p<0.01; ES=0.64-0.68) and was consistently ranked as the easiest grip for any load. Males achieved significantly greater PV than females at 50% and 70% (p<0.01; ES=1.72-1.92). Hand orientation did not significantly impact PV. A MG may be beneficial in reducing the overall perceived technical difficulty when performing a maximal DL. Athletes aiming to maximise muscle activation and potentially develop their grip strength should utilise a DOH grip or HG.
... ont, back, was the spine kept neutral?) active certain muscle groups differently (Clark et al. 2012). We also know that movements such as the deadlift (again, multiple forms can be used) activate specific local and global core muscles while having high activity from important "core-limb transfer muscles" such as the hamstrings and latissimus dorsi (Beggs. 2011). ...
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The performance of ten elite powerlifters were analyzed in a simulated competition environment using three-dimensional cinematography and surface electromyography while bench pressing approximately 80% of maximum, a maximal load, and an unsuccessful supramaximal attempt. The resultant moment arm (from the sagittal and transverse planes) of the weight about the shoulder axis decreased throughout the upward movement of the bar. The resultant moment arm of the weight about the elbow axis decreased throughout the initial portion of the ascent of the bar, recording a minimum value during the sticking region, and subsequently increased throughout the remainder of the ascent of the bar. The electromyograms produced by the prime mover muscles (sternal portion of pectoralis major, anterior deltoid, long head of triceps brachii) achieved maximal activation at the commencement of the ascent phase of the lift and maintained this level essentially unchanged throughout the upward movement of the bar. The sticking region, therefore, did not appear to be caused by an increase in the moment arm of the weight about the shoulder or elbow joints or by a minimization of muscular activity during this region. A possible mechanism which envisages the sticking region as a force-reduced transition phase between a strain energy-assisted acceleration phase and a mechanically advantageous maximum strength region is postulated.
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Forearm pronation and supination, and increased muscular activity in the wrist extensors have been both linked separately to work-related injuries of the upper limb, especially humeral epicondylitis. However, there is a lack of information on forearm torque strength at ranges of elbow and forearm angles typical of industrial tasks. There is a need for strength data on forearm torques at different upper limb angles to be investigated. Such a study should also include the measurement of muscular activity for the prime torque muscles and also other muscles at possible risk of injury due to high exertion levels during tasks requiring forearm torques.
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The purpose of this investigation was to compare trunk muscle activity during stability ball and free weight exercises. Nine resistance-trained men participated in one testing session in which squats (SQ) and deadlifts (DL) were completed with loads of approximately 50, 70, 90, and 100% of one-repetition maximum (1RM). Isometric contractions during 3 stability ball exercises (quadruped (QP), pelvic thrust (PT), ball back extension (BE)) were also completed. During all exercises, average integrated electromyography (IEMG) from the rectus abdominus (RA), external oblique (EO), longissimus (L1) and multifidus (L5) was collected and analyzed. Results demonstrate that when expressed relative to 100% DL 1RM, muscle activity was 19.5 +/- 14.8% for L1 and 30.2 +/- 19.3% for L5 during QP, 31.4 +/- 13.4% for L1 and 37.6 +/- 12.4% for L5 during PT, and 44.2 +/- 22.8% for L1 and 45.5 +/- 21.6% for L5 during BE. IEMG of L1 during SQ and DL at 90 and 100% 1RM, and relative muscle activity of L5 during SQ and DL at 100% 1RM was significantly greater (P < or = 0.05) than in the stability ball exercises. Furthermore, relative muscle activity of L1 during DL at 50 and 70% 1RM was significantly greater than in QP and PT. No significant differences were observed in RA and EO during any of the exercises. In conclusion, activity of the trunk muscles during SQs and DLs is greater or equal to that which is produced during the stability ball exercises. It appears that stability ball exercises may not provide a sufficient stimulus for increasing muscular strength or hypertrophy; consequently, the role of stability ball exercises in strength and conditioning programs is questioned. SQs and DLs are recommended for increasing strength and hypertrophy of the back extensors.
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This paper investigated whether the ratio of medial-lateral hamstring muscular activation could be altered with changes in foot rotation position (both internal and external rotation) during three standard lower limb exercises. It has been suggested that those with medial compartment knee OA activate the lateral hamstrings more than the medial to help unload the diseased compartment; therefore, preferential activation of this muscle during lower limb exercise may help to further decrease the stresses on the articular cartilage and be an effective intervention for knee OA and lateral hamstring injury. Thirteen healthy young adult subjects were tested and average medial and lateral hamstring EMG data during the full exercise, as well as the concentric and eccentric phases, were used to calculate the medial-lateral (M-L) hamstring activation ratio for each exercise and foot position. Results suggest that internal foot rotation increases the M-L hamstring activation ratio while external foot rotation decreases this ratio. Therefore, altering the position of the foot during standard lower limb exercise can help selectively activate the medial or lateral hamstring muscle groups. This selective activation may have implication in treating symptoms of knee osteoarthritis and hamstring injury; but, longitudinal intervention studies would be needed to determine clinical utility.
Article
The purpose of this study was to determine whether 7 weeks of standardized (same number and duration of repetitions, sets and rest strictly identical) electromyostimulation training of the elbow flexor muscles would induce strength gains equivalent to those of voluntary isometric training in isometric, eccentric and concentric contractions. Twenty-five males were randomly assigned to an electromyostimulated group (EMS, n=9), a voluntary isometric group (VOL, n=8), or a control group (CON, n=8). Maximal voluntary isometric, eccentric and concentric strength, electromyographic (EMG) activity of the biceps and triceps brachii muscles, elbow flexor muscle activation (twitch interpolation technique) and contractile properties were assessed before and after the training period. The main findings were that the isometric torque gains of EMS were greater than those of VOL after the training period (P<0.01) and that the eccentric and concentric torque gains were equivalent. In both groups, we observed that the mechanical twitch (Pt) was increased (P<0.05) and that torque improvements were not mediated by neural adaptations. Considering the respective intensities of the training programs (i.e., submaximal contractions for EMS versus maximal for VOL), it can be concluded that electromyostimulation training would be more efficient than voluntary isometric training to improve both isometric and dynamic strength.