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The main aim of this study was to examine the relationship between body weight, absolute and relative strength and power variables in a flywheel Romanian deadlift. A secondary aim was to assess the inter-day reliability of a novel power assessment protocol previously used to determine the inertial load that produced the maximum power output in Flywheel Inertia Training. Ten physically active males took part in this study. Participants had some experience with flywheel devices, but all had a minimum of 24 months of traditional resistance training experience. The first testing session consisted of three sets of 10 repetitions with a different inertial load for each set (0.050, 0.075, and 1.00 kg·m2). Each set's first and second repetitions were used to build momentum and were excluded from data analysis. The order of inertial load used in each trial was standardized for all participants: first, 0.050 kg·m2, second, 0.075 kg·m2, and last, 0.100 kg·m2. The secondary testing session followed the same procedure as the first. No statistically significant (p < 0.05) effect was found between any of the variables in the correlation analysis. There were large positive correlations between the 1 repetition max flywheel Romanian deadlift and peak concentric power, relative strength, and peak concentric and eccentric peak powers. Both body weight and relative strength showed moderate negative correlations with % eccentric overload, whereas moderate positive correlations were observed between 1RM and peak eccentric power. Both concentric power and eccentric power showed excellent reliability, while the reliability for % eccentric overload ranged from poor to excellent depending on the inertial load. In conclusion, this study shows that a protocol to assess the maximum power output has excellent reliability for both ECC and CON power and may be used in future flywheel training. The results also showed that body weight, maximum strength, and relative strength were not largely related to power variables. An individualized approach to flywheel training is required. [ABSTRACT FROM AUTHOR]

The main purpose of this review was to systematically analyze the literature concerning studies which have investigated muscle activation when performing the Deadlift exercise and its variants. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Statement (PRISMA). Original studies from inception until March 2019 were sourced from four electronic databases including PubMed, OVID, Scopus and Web of Science. Inclusion criteria were as follows: (a) a cross-sectional or longitudinal study design; (b) evaluation of neuromuscular activation during Deadlift exercise or variants; (c) inclusion of healthy and trained participants, with no injury issues at least for six months before measurements; and (d) analyzed "sEMG amplitude", "muscle activation" or "muscular activity" with surface electromyography (sEMG) devices. Major findings indicate that the biceps femoris is the most studied muscle, followed by gluteus maximus, vastus lateralis and erector spinae. Erector spinae and quadriceps muscles reported greater activation than gluteus maximus and biceps femoris muscles during Deadlift exercise and its variants. However, the Romanian Deadlift is associated with lower activation for erector spinae than for biceps femoris and semitendinosus. Deadlift also showed greater activation of the quadriceps muscles than the gluteus maximus and hamstring muscles. In general, semitendinosus muscle activation predominates over that of biceps femoris within hamstring muscles complex. In conclusion 1) Biceps femoris is the most evaluated muscle, followed by gluteus maximus, vastus lateralis and erector spinae during Deadlift exercises; 2) Erector spinae and quadriceps muscles are more activated than gluteus maximus and biceps femoris muscles within Deadlift exercises; 3) Within the hamstring muscles complex, semitendinosus elicits slightly greater muscle activation than biceps femoris during Deadlift exercises; and 4) A unified criterion upon methodology is necessary in order to report reliable outcomes when using surface electromyography recordings. [ABSTRACT FROM AUTHOR]

Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC) assessment. Twenty-four previously untrained men (mean age  = 24 years) were randomly assigned to training (n = 15) or control (n = 9) groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC) and y-intercepts (pps) of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70), but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units. [ABSTRACT FROM AUTHOR]

Abstract: A 10N·m dead weight torque standard machine (10-N·m-DWTSM) has been under development at NMIJ/AIST since 2006 to expand the range of the torque standard. Estimation of the sensitivity limit of the fulcrum is one of the most important issues to realize a precise reference torque of small capacity by using a dead weight torque standard machine. In this study, a torque transducer was installed on the 10-N·m-DWTSM in order to keep the moment-arm on the horizontal line (balancing). The sensitivity limit of the fulcrum under real calibration conditions was estimated by reading the change in the output from the torque measuring device (TMD: the torque transducer with a cable and an indicating device) when small weights were loaded or unloaded. The small weights used in the experiment were 0.5mg, 1mg, 10mg, and 100mg. Equivalent radial loads from 0.1N·m to 10N·m were imposed on the fulcrum during the sensitivity measurement. As a result, the sensitivity limit of the fulcrum was confirmed to be sufficient to load at least 0.5mg. A relative sensitivity limit of the fulcrum of 2.5×10−5 and relative reproducibility of the sensitivity limit of the fulcrum of 1.7×10−6 could be obtained within the calibration range from 0.1N·m to 10N·m. It is also important to develop small-rated-capacity torque transducers that can be used as a transfer standard. Therefore, a transducer with a rated capacity of 1N·m was developed in parallel with the development of the 10-N·m-DWTSM. The stability of the 1N·m TMD has been evaluated over a period of 1year. [Copyright &y& Elsevier]

The article discusses the versatility of powerlifting as an activity for high school students, noting that people of various ages, genders, and sizes are able to participate in the sport. It discusses safety and equipment prerequisites for a high school powerlifting program, the options of having either an elective course or intramural competition, and different lifts such as the squat, the bench press, and the deadlift.

The article presents the results of a study which investigated whether a dynamic stretching warmup could be combined with various other exercises, such as plyometrics or deadlifts, in order to improve vertical jump performance. An overview of related previous research is provided, along with details of the experimental protocol.

The article presents a study that investigated the kinematics and kinetics associated with the deadlift exercise performed with two different barbells and several submaximal loads. Participants included 19 male powerlifters who performed deadlifts with both a straight bar and hexagonal bar. Overall, it appeared the hexagonal lift was a better exercise than the straight-bar lift.

The article reports on research which was conducted to compare the production of force and paraspinal muscle activity between dead lifts carried out in a standard way and with different instability devices. Researchers evaluated 31 athletes. They found that the use of instability devices in dead lift training did not increase performance or provide greater activation of the paraspinal muscles.

The article reports on research conducted to compare and contrast biomechanical parameters between the conventional style deadlift and the back squat performed by 25 lifters competing in regional powerlifting championship. Researchers found that the back squat represents a synergistic or simultaneous movement, while the deadlift demonstrates a sequential or segmented movement They also found that no crossover effects exist between the two lifts.

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), longissimas (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 ≤ 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. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the relationship between quadriceps resistance training exercises and squat exercises when predicting quadriceps exercise loads. Exercises discussed include the dead lift, lunge, leg extension, and step-up. The author presents an equation used to predict the maximum load used for six-repetition exercises.