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Objectives: To determine if force differences exist between isometric pulling positions corresponding to key positions of the deadlift. Design: Cross-sectional evaluation of isometric strength Methods: 14 powerlifters performed isometric pulls on a force plate at 3 key positions related to the deadlift (at the floor, just above the patella, and 5-6 cm short of lockout) and in the mid thigh pull position (MTP). A 1x4 repeated measures ANOVA was used to ascertain differences between the various pulling positions tested. Bonferroni-adjusted paired samples t-tests were used post-hoc. Results: Forces generated at each bar height were significantly different (F(3,39) = 51.058, p<0.05, η2=0.80). Paired samples t-tests showed significant differences between positions, revealing a trend of greater force generation at increasing heights for positions corresponding to the deadlift. Force generated in the mid thigh pull position was significantly higher than any other position. Conclusion: In positions corresponding to the deadlift, force generation increases at higher bar heights.
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P
owerlifting is a sport made up of three events, the squat,
bench press and deadlift. For each event, the ultimate goal
is to lift as much weight as is possible. In the deadlift, a lifter
lifts the barbell off of the floor until standing upright. The lift
is finished upon extending the knees and hips with scapula
retracted. Two styles of the deadlift are used in competition.
The sumo style uses a wide foot stance, upright posture, and a
grip width that is narrower than the feet.
1
Conversely, the
conventional style deadlift uses a narrow foot stance, generally
a more bent-over posture, and a grip outside of the legs.
Three key phases have been identified in the literature for
the conventional deadlift.
2-4
The first phase, or lift-off, occurs
when the lifter first applies force to the bar and the bar rises off
of the floor. The second phase, knee passing, occurs when the
bar moves from below to above the knee. The third phase, or
lift completion, occurs when the lifter transitions into a full
upright position. While these specific regions of the deadlift
are known, little has been done to examine how each position
might contribute to deadlift performance. The most
disadvantageous position represents a limiting factor in overall
performance, thus identification of this position may lead to
better training prescriptions.
To the authors’ knowledge, no literature exists that assesses
the force generation capabilities of lifters in these phases of the
deadlift, however in a number of studies examining the
isometric mid thigh pull (MTP), a weightlifting-specific
position, a variety of athletes produced high levels of peak
forces.
5-7
Peak force measured in these studies showed
moderate to strong relationships with dynamic mid-thigh pulls,
jumps and a number of other dynamic measures. Therefore,
since little is known about the force generation capabilities of
lifters in the key phases of the deadlift, the purpose of the
study was to evaluate the isometric maximum strength of
powerlifters in bar positions corresponding to key phases of
the deadlift and also to compare those positions to the MTP,
given the strong relationship the MTP shares with a variety of
dynamic measures.
Methods
Experimental Approach to the Problem
Data obtained in an athlete monitoring program were
assessed using a repeated measures design to assess peak force
production differences between key positions of the deadlift. A
repeated measures ANOVA and paired t-tests were used to
assess force differences between positions.
Athletes
Fourteen competitive powerlifters who could deadlift a
minimum of 2.5 x body mass (BdM) using the conventional
style using only a belt or competed regularly volunteered for
this investigation. Based upon training history questionnaires
all subjects reported that they did not regularly perform
weightlifting movements or their variants. Some lifters
reported using the sumo style most often in competition (n=4),
32
Short Communication
Isometric Strength of Powerlifters in Key Positions
of the Conventional Deadlift
George K. Beckham, Hugh S. Lamont, Kimitake Sato, Michael W. Ramsey, G. Gregory Haff, Michael H. Stone
Objectives: To determine if force differences exist between isometric pulling positions corresponding to key positions of the
deadlift.
Design: Cross-sectional evaluation of isometric strength
Methods: 14 powerlifters performed isometric pulls on a force plate at 3 key positions related to the deadlift (at the floor,
just above the patella, and 5-6 cm short of lockout) and in the mid thigh pull position (MTP). A 1x4 repeated measures
ANOVA was used to ascertain differences between the various pulling positions tested. Bonferroni-adjusted paired
samples t-tests were used post-hoc.
Results: Forces generated at each bar height were significantly different (F(3,39) = 51.058, p<0.05, η
2
=0.80). Paired
samples t-tests showed significant differences between positions, revealing a trend of greater force generation at
increasing heights for positions corresponding to the deadlift. Force generated in the mid thigh pull position was
significantly higher than any other position.
Conclusion: In positions corresponding to the deadlift, force generation increases at higher bar heights.
(Journal of Trainology 2012;1:32-35)
Key words: powerlifting
strength testing
performance monitoring
maximum strength
isometric mid thigh pull
Received October 17, 2012; accepted November 12, 2012
From Center of Excellence for Sport Science and Coach Education, Department of Kinesiology, Leisure, and Sports Science, East Tennessee State
University, Johnson City, TN, USA (G.K.B., H.S.L., K.S., M.W.R., M.H.S), and Centre for Exercise and Sport Science Research, Edith Cowan University,
Perth, Australia (G.G.H., M.H.S).
Communicated by Takashi Abe, PhD
Correspondence to Mr. George K. Beckham, East Tennessee State University, PO Box 70654. Email: gkbeckham@gmail.com
Journal of Trainology 2012:1:32-35 ©2012 The Active Aging Research Center http://trainology.org/
Beckham et al. Isometric Strength of Powerlifters in Key Positions of the Conventional Deadlift 33
but all lifters reported training regularly using the conventional
style (n=14, age range: 18-39, height: 178.6±9.8cm, BdM:
109.9±20kg, conventional deadlift 1-RM: 248.5±18kg). Each
subject was screened by questionnaire for injury prior to
testing. Athletes were informed of all testing procedures and
possible risks, and voluntarily signed an informed consent
document as outlined by University Institutional Review
Board policy.
Warm-up procedures
The warm-up routine was a standardized protocol with a
small amount of possible modification (within the specified
range) to more closely match the typical warm-up routine of
the lifter. Warm-ups were as follows: 2-5 repetitions at 35% of
1-RM, followed by 90 seconds rest, 2-3 repetitions at 50%
1-RM, followed by 120 seconds rest, 1-2 repetitions at 65%
1-RM, followed by 150 seconds rest, then 1 repetition at 75%
1-RM, followed by 180 seconds rest. Warm-up loads were
determined using the athletes’ belt-only conventional personal
records.
Isometric Testing Procedures
All isometric testing was completed in a custom designed
power rack that allows fixation at any height. Athletes stood
on a 91.4 x 91.4 cm force plate (Rice Lake Weighing Systems,
Rice Lake, WI) to measure vertical ground reaction forces. Bar
heights for each testing condition were chosen to correspond
to the three key positions achieved in the deadlift and the
isometric mid-thigh pull. For the first height, the center of the
bar was placed at 22.5 cm from the floor to correspond to the
position of the barbell in the start of the deadlift. The second
bar position was placed immediately superior to the patella
from standing. The third corresponded to the same body
position as used in the MTP.
5, 6
The fourth position used the
same bar height as the third, but with a self-selected body
position corresponding to one that would be achieved in a
deadlift. Pilot testing indicated that the fourth height results in
a body position with the bar 4-6 cm from deadlift lockout.
Intra-session test-retest reliability (intraclass correlation,
coefficient of variation, respectively with 90% CI’s for each)
of peak force for each position was excellent: floor: 0.99
(0.98-1.0), 1.2% (0.9%-1.8%), knee: 0.98 (0.96-0.99), 2.0%
(1.5%-2.9%), IMTP: 0.92 (0.80-0.96), 5.0% (3.8%-7.5%),
lockout: 0.88 (0.70-0.94), 4.6% (3.5%-6.9%).
Each condition was performed in order, 1-4, to maintain
standardization among athletes and result in a uniform fatigue.
Pilot testing indicated that forces and perceived difficulty
increased as the athletes used the higher bar positions, thus the
order was chosen to correspond to what was likely least
fatiguing to most fatiguing. The conditions were separated by
10 minutes of rest, during which time the athletes remained
seated. Athletes were secured to the bar using lifting straps and
athletic tape. Each subject assumed the position he would be
using for the pull condition, and once body position was
stabilized (verified by visual monitoring of both the athlete
and force trace), the athlete was given a countdown. Nominal
pre-tension was allowed to minimize slack in the subject’s
body prior to the pull (monitored by force-trace and instruction
to the lifter) to ensure that little or no vertical acceleration of
the athlete occurred. The subject performed two warm-up
attempts separated by 90-120 seconds, each at a subject-
estimated 50% and 75% of maximum. The athletes then
performed 2 to 3 maximal attempts for 3-4 seconds each,
separated by 2-3 minutes. The attempt was terminated when a
plateau or consistent decrease in force was observed. A third
trial was only performed if a ≥250N difference in PF was
observed between trials, a countermovement was observed, or
if the athlete did not follow directions.
6
The highest observed force from each pull obtained using a
custom analysis program (National Instruments, Austin, TX)
was designated peak force (PF). PF measurements from both
trials were averaged. Peak force was allometrically scaled
(APF) using the equation [y=result∙BdM
-2/3
].
6,8
Analog data from the force plate were amplified and
conditioned (low-pass at 16 Hz; Transducer Techniques,
Temecula, California). An AD converter (DAQCard-6063E,
National Instruments, Austin, TX) allowed for collection at
1000 Hz and further low-pass filtering using a software-based
4
th
Order Butterworth filter at 100 Hz.
Statistical Analysis
For the purpose of comparing kinetic measures at each of
the four pulling positions, a repeated measures ANOVA (RM
ANOVA) was used for each dependent variable considered,
using Bonferroni adjusted paired t-tests (p=0.008) for post-
hoc analysis. RM ANOVA and post-hoc tests were performed
for unscaled and allometrically scaled force. Alpha was
designated at p=0.05. All statistical analysis was performed
using SAS 9.2 (Statistical Analysis System, SAS Institute Inc.,
Cary, NC). Effect sizes were evaluated with the method of
Hopkins.
9
Results
PF and APF measures can be found in Table 1. There was a
significant main effect for PF (F(3,39) = 87.44, p<0.0001),
with η
2
of 0.871. APF measures were significant for main
effect (F(3,39) = 88.23, p<0.05) with η
2
of 0.872. Results of
paired t-tests can be found in Table 1. Effect sizes of paired
t-tests for PF and APF were as follows: floor vs. knee, 1.50,
1.97; floor vs. MTP 3.66, 4.22; floor vs lockout 3.04, 3.08;
knee vs. MTP 2.10, 2.80; knee vs. lockout 1.40, 1.52; MTP vs.
lockout 1.23, 1.27.
Discussion
Athletes produced different PFs at each position (floor, knee,
MTP, lockout). The changing bar height resulted in different
body positions for each pull, and thus a differing ability to
apply force. Interestingly, positions directly related to deadlift
performance (floor, knee, lockout) tended to increase force in
the higher bar positions. PF and APF in the floor position were
significantly less than both the knee and lockout positions
(effect size of large to very large). There was also a significant
Journal of Trainology 2012;1:32-3534
difference between knee and lockout positions (with large
effect size). This finding may be due to a number of reasons.
Brown & Abani
2
found that horizontal hip moment to the bar
center of mass (COM) decreased with higher bar positions in
the deadlift. While Escamilla et al.
1
did not test for significant
differences, they reported a trend of decreasing horizontal
moment arm to the barbell COM at the ankle, hip and knee as
the lifter ascended from lift-off to knee passing. This decreased
moment at higher positions may allow for better mechanical
advantage at the hip, thus increasing the resultant generation of
upward force on the bar.
One confounding issue is the fact that two studies have
found that the sticking region occurs at a point roughly around
the knee.
1, 3
Because biomechanical disadvantage causes the
sticking point to occur at a certain range of motion, the total
force generating capability at that position should be reduced
(net extensor moment and force applied to the bar). Therefore,
based on the two aforementioned studies, the force generating
capabilities of deadlifters at the knee position should be less
than the floor position, not more, as was found in the present
study. It is possible that anthropometric characteristics
predispose one to certain sticking points, but no known
research exists to assert this. Another possibility is that in the
Escamilla et al.
1
and Hales et al.
3
studies the lifters were using
a powerlifting deadlift suit. If this was the case, then the
sticking regions of the lifts may be higher due to the assistance
afforded the lifter by lifting suits.
10
Also possible is that the
position used by athletes in the present study is different than
what athletes use in a maximal deadlift. If the isometric pull
allows for a more ideal body position than is attained during
the deadlift, greater forces might be achieved, thus
representing a possible limitation of this study. Further
research should confirm this.
It is interesting that the MTP position allowed the lifters to
produce the greatest amount of force, despite the lockout
position being more similar in position to the deadlift. The
lifters generally performed well in the lockout position
(understandable given that they regularly train a movement
that requires it, i.e. the deadlift, and do not regularly train in
the MTP position); therefore the MTP position must provide a
substantial mechanical advantage that overcomes even the
frequent training in the deadlift-specific position. The greater
Table 1. Results of isometric testing and paired t-tests
Measure Position Mean ± SD Significance
Peak Force (N)
Floor 3380.0 ± 377.0 †, ‡, §
Knee 4093.0 ± 559.0 *, ‡, §
Mid-Thigh Pull 5829.0 ± 867.0 *, †, §
Lockout 4910.0 ± 605.0 *, †, ‡
Allometrically Scaled
Peak Force (N.kg
-1
)
Floor 148.5 ± 12.7 †, ‡, §
Knee 179.8 ± 18.6 *, ‡, §
Mid-Thigh Pull 256.4 ± 33.9 *, †, §
Lockout 216.6 ± 28.6 *, †, ‡
* = significantly different than floor position p <0.001
† = significantly different than knee position p <0.001
‡ = significantly different than MTP position p <0.001
§ = significantly different than lockout position p <0.001
Figure 1. Example of lifter in MTP position (left) compared to lockout (right)
Beckham et al. Isometric Strength of Powerlifters in Key Positions of the Conventional Deadlift 35
forces produced in the MTP position over the other three
positions may be explained by a number of things. First,
simple observation showed a marked difference in position
even between the MTP and the position of second greatest
force (lockout). The MTP position is rather upright, with the
knees bent. Powerlifters, in mimicking the deadlift, are in a
relatively straight legged position and somewhat bent over the
bar. Figure 1 shows an example of the differing position for
one of the athletes. The lockout position likely creates a
greater moment on the lower back and hips, which may limit
performance. The greater knee bend used in the MTP position
probably provides a force-production advantage, as the
powerful extensor forces of the quadriceps muscles are used to
a greater extent. The gluteus maximus may also be in a more
favorable position for resultant force production against the
bar, assuming a smaller hip moment, as was found in Brown &
Abani
2
and Escamilla et al.
1
Conclusion
Powerlifters in this study generated substantially different
amounts of force in each position. Changing mechanical
advantages probably contribute to the difference in forces, but
further research is needed to confirm this. Despite the
advantage of regular training in the deadlift-specific positions
(floor, knee and lockout), lifters still generated far more force
in the MTP. The MTP appears to represent the position of
greatest force output, even in lifters who train regularly in the
other positions. Lower force production capabilities in the
lower positions represent a limiting factor for deadlift
performance, thus an emphasis in training of the lower ranges
of motion of the deadlift may elicit greater gains.
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... For example, isometric strength testing via the isometric mid-thigh pull (IMTP) is a preferable means to analyze maximal force production rather than 1-RM testing, as IMTPs are relatively simple to administer, time efficient, reduce the risk of injury, and possess high degrees of reliability under the correct testing conditions [6][7][8][9]. Additionally, despite being an isometric test (i.e., no physical movement or displacement of body segments), measures from the IMTP correlate to performance in dynamic movements of powerlifting [10,11], weightlifting [12], sprinting [13], and jumping [14,15]. Another test, the countermovement jump (CMJ), is used (often in conjunction with IMTPs) for athlete testing to identify changes in power performance [16], resiliency to fatigue [17][18][19], and risk for injury [20]. ...
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Abstract: The purpose of this study was to evaluate intrasession reliability of countermovement jump (CMJ) and isometric mid-thigh pull (IMTP) force–time characteristics, as well as relationships between CMJ and IMTP metrics. Division I sport and club athletes (n = 112) completed two maximal effort CMJ and IMTP trials, in that order, on force plates. Relative and absolute reliability were assessed using intraclass correlation coefficients (ICCs) > 0.80 and coefficients of variation (CVs) < 10%. Intrasession reliability was acceptable for the majority of the CMJ force–time metrics except for concentric rate of force development (RFD), eccentric impulse and RFD, and lower limb stiffness. The IMTP’s time to peak force, instantaneous force at 150 ms, instantaneous net force, and RFD measures were not reliable. Statistically significant weak to moderate relationships (r = 0.20–0.46) existed between allometrically scaled CMJ and IMTP metrics, with the exception of CMJ eccentric mean power not being related with IMTP performances. A majority of CMJ and IMTP metrics met acceptable reliability standards, except RFD measures which should be used with caution. Provided CMJs and IMTPs are indicative of distinct physical fitness capabilities, it is suggested to monitor athlete performance in both tests via changes in those variables that demonstrate the greatest degree of reliability.
... 72 For readers interested in the use of the IMTP with weightlifters, a detailed review was recently published by Stone et al. 117 Despite the IMTP positioning being specific to the WL movements, strong correlations have been found between it and both the squat 28,90,91 and deadlift; 32 however, these studies were not conducted using powerlifters as subjects. Beckham et al, 14 using competitive powerlifters, compared the IPF performed in different positions that corresponded closer to a conventional deadlift to the IMTP. However, to the authors' knowledge, no longitudinal investigation has used this type of testing with powerlifters. ...
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Barbell strength sports such as weightlifting (WL) and powerlifting (PL) have been slow to adopt modern athlete monitoring practices. Obstacles such as a lack of resources, experience, and knowledge dealing with athlete monitoring stand in the way of their implementation into these sports. Therefore, the purposes of this review are: 1) to synthesise the scientific literature most relevant to the monitoring of strength athletes, and 2) to provide practical recommendations to the strength sport coach for implementing an athlete monitoring programme.
... Reason being, isometric tests are relatively simple to administer and time efficient, reduce the risk of injury in comparison to one-repetition maximum testing, and are very reliable under the correct and consistent conditions [42][43][44]. Additionally, even though the IMTP is isometric by nature (it does not involve physical movement or displacement of body segments), measures from the IMTP correlate to performance in dynamic movements of powerlifting [86], weightlifting [87], sprinting [88], and jumping [89]. Most importantly, the IMTP and isometric squat do not require the extensive familiarization periods that may be associated with a traditional one-repetition maximal test, which requires specific skill development in the weight room (e.g., becoming highly proficient in the back squat, bench press, deadlift, etc.). ...
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A necessarily high standard for physical readiness in tactical environments is often accompanied by high incidences of injury due to overaccumulations of neuromuscular fatigue (NMF). To account for instances of overtraining stimulated by NMF, close monitoring of neuromuscular performance is warranted. Previously validated tests, such as the countermovement jump, are useful means for monitoring performance adaptations, resiliency to fatigue, and risk for injury. Performing such tests on force plates provides an understanding of the movement strategy used to obtain the resulting outcome (e.g., jump height). Further, force plates afford numerous objective tests that are valid and reliable for monitoring upper and lower extremity muscular strength and power (thus sensitive to NMF) with less fatiguing and safer methods than traditional one-repetition maximum assessments. Force plates provide numerous software and testing application options that can be applied to military's training but, to be effective, requires the practitioners to have sufficient knowledge of their functions. Therefore, this review aims to explain the functions of force plate testing as well as current best practices for utilizing force plates in military settings and disseminate protocols for valid and reliable testing to collect key variables that translate to physical performance capacities.
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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. 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.
Chapter
The testing and assessment of resistance training exercises is a fundamental aspect for coaches and athletes. Through the force-time data measured by force plates, we have the possibility to calculate velocity, displacement, work, and power values of the centre of mass. This chapter has a theory section where we explain why force plates are useful to evaluate isometric and ballistic actions during resistance training. Also, we explore how we can obtain velocity, displacement, power and work variables from force-time data through the impulse method. The chapter contains a practice section where we response some key questions when setting up a force plate to assess athletes’ physical performances. Then, we describe how to perform an Isometric Mid Thigh Pull Test (IMTP) and a Countermovement Jump Test (CMJ). We explain how we can obtain biomechanical variables from both tests and we discuss about the biomechanical variables that provide important information to interpret correctly the IMTP and CMJ tests. Finally, we added a filling the gap section where we provide several recommendations on how to implement the evidence-based theory in real life applied sports environments.
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To investigate the relationship between maximum strength and differences in jump height during weighted and unweighted (body weight) static (SJ) and countermovement jumps (CMJ). Sixty-three collegiate athletes (mean +/- SD; age= 19.9 +/- 1.3 y; body mass = 72.9 +/- 19.6 kg; height = 172.8 +/- 7.7 cm) performed two trials of the SJ and CMJ with 0 kg and 20 kg on a force plate; and two trials of mid-thigh isometric clean pulls in a custom rack over a force plate (1000-Hz sampling). Jump height (JH) was calculated from flight time. Force-time curve analyses determined the following: isometric peak force (IPF), isometric force (IF) at 50, 90, and 250 ms, and isometric rates of force development (IRFD). Absolute and allometric scaled forces, [absolute force/(body mass(0.67))], were used in correlations. IPF, IRFD, F50(a), F50, F90, and F250 showed moderate/strong correlations with SJ and CMJ height percent decrease from 0 to 20 kg. IPF(a) and F250(a) showed weak/moderate correlations with percent height decrease. Comparing strongest (n = 6) to weakest (n = 6): t tests revealed that stronger athletes (IPF(a)) performed superior to weaker athletes. Data indicate the ability to produce higher peak and instantaneous forces and IRFD is related to JH and to smaller differences between weighted and unweighted jump heights. Stronger athletes jump higher and show smaller decrements in JH with load. A weighted jump may be a practical method of assessing relative strength levels.
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This study documented characteristics of the dead lift of teenage lifters. Films of 10 "skilled" and 11 "unskilled" contestants in a Michigan Teenage Powerlifting Championship provided data for analysis. Equations of motion, force, and moments were developed for a multisegment model of the lifters' movement in the sagittal plane and applied to the film data. Analysis was limited to 1) body segment orientations, 2) vertical bar accelerations, 3) vertical joint reaction forces, 4) segmental angular accelerations, 5) horizontal moment arms of the bar to selected joints, and 6) intersegmental resultant moments. Significant differences (P less than 0.05) in body segment orientation indicated a more upright posture at lift-off in the skilled group. Maximum vertical bar acceleration and angular acceleration of the trunk tended to occur near lift-off in the skilled lifters. The unskilled subjects demonstrated greater variability and magnitude in linear and angular acceleration parameters. In all lifters, maximum vertical force was experienced at the ankle joint. Within each subject, the hip joint experienced the greatest torque because of the relatively large horizontal moment arm of the bar (dominant mass in the system) to this joint. In all subjects, the magnitude of the mass lifted, and not the technique, was the primary determinant in the intersegmental resultant moment acting at the hip and the vertical force experienced at the ankle, knee, and hip joints.
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Strength athletes often employ the deadlift in their training or rehabilitation regimens. The purpose of this study was to quantify kinematic and kinetic parameters by employing a three-dimensional analysis during sumo and conventional style deadlifts. Two 60-Hz video cameras recorded 12 sumo and 12 conventional style lifters during a national powerlifting championship. Parameters were quantified at barbell liftoff (LO), at the instant the barbell passed the knees (KP), and at lift completion. Unpaired t-tests (P < 0.05) were used to compare all parameters. At LO and KP, thigh position was 11-16 degrees more horizontal for the sumo group, whereas the knees and hips extended approximately 12 degrees more for the conventional group. The sumo group had 5-10 degrees greater vertical trunk and thigh positions, employed a wider stance (70 +/- 11 cm vs 32 +/- 8 cm), turned their feet out more (42 +/- 8 vs 14 +/- 6 degrees). and gripped the bar with their hands closer together (47 +/- 4 cm vs 55 +/- 10 cm). Vertical bar distance, mechanical work, and predicted energy expenditure were approximately 25-40% greater in the conventional group. Hip extensor, knee extensor, and ankle dorsiflexor moments were generated for the sumo group, whereas hip extensor, knee extensor, knee flexor, and ankle plantar flexor moments were generated for the conventional group. Ankle and knee moments and moment arms were significantly different between the sumo and conventional groups, whereas hip moments and moments arms did not show any significantly differences. Three-dimensional calculations were more accurate and significantly different than two-dimensional calculations, especially for the sumo deadlift. Biomechanical differences between sumo and conventional deadlifts result from technique variations between these exercises. Understanding these differences will aid the strength coach or rehabilitation specialist in determining which deadlift style an athlete or patient should employ.