Body Stuff Levantamento Terra

: A three-dimensional biomechanical analysis of sumo and conventional style deadlifts.

Escamilla RF, Francisco AC, Fleisig GS, Barrentine SW, Welch CM, Kayes AV, Speer KP, Andrews JR.

Division of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710, USA. rescamil@duke.edu

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

PMID: 10912892 [PubMed - indexed for MEDLINE]

: Biomechanical analysis of the deadlift during the 1999 Special Olympics World Games.

Escamilla RF, Lowry TM, Osbahr DC, Speer KP.

Michael W. Krzyzewski Human Performance Laboratory, Division of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710, USA. rescamil@duke.edu

PURPOSE: Improper lifting techniques may increase injury risks and decrease performance. The aim of this study was to compare and contrast biomechanical parameters between sumo and conventional style deadlifts and between high- and low-skilled lifters who participated in the powerlifting event during the 1999 Special Olympics World Games. METHODS: Two synchronized video cameras collected 60 Hz of data from 40 subjects. Parameters were quantified at barbell liftoff (LO), when the barbell passed the knees (KP), and at lift completion. RESULTS: Compared with the conventional group, the sumo group had a 100% greater stance width, 20% smaller hand width, 10% less vertical bar distance, a more vertical trunk at LO, a more horizontal thigh at LO and KP, a less vertical shank at KP, and greater forefoot abduction. The sumo group generated ankle dorsiflexor, knee extensor, and hip extensor moments, whereas the conventional group produced ankle plantar flexor, knee flexor and extensor, and hip extensor moments. Compared with low-skilled lifters, high-skilled lifters had a 40% greater barbell load, 15% greater stance width (sumo group only), greater knee flexion at LO (conventional group only), greater knee extension at KP, a less vertical shank position at LO (sumo group only), 15% less vertical bar distance, less first peak bar velocity between LO and KP (conventional group only), smaller plantar flexor and hip extensor moment arms at LO and KP, and greater knee extensor moment arms at LO. CONCLUSIONS: The sumo deadlift may be more effective in working ankle dorsiflexors and knee extensors, whereas the conventional deadlift may be more effective in working ankle plantar flexors and knee flexors. High-skilled lifters exhibited better lifting mechanics than low-skilled lifters by keeping the bar closer to the body, which may both enhance performance and minimize injury risk.

PMID: 11474337 [PubMed - indexed for MEDLINE]

: An electromyographic analysis of sumo and conventional style deadlifts.

Escamilla RF, Francisco AC, Kayes AV, Speer KP, Moorman CT 3rd.

Michael W. Krzyzewski Human Performance Laboratory, Division of Orthopaedic Surgery, Duke University Medical Center, P.O. Box 3435, Durham, NC 27710, USA. rescamil@duke.edu

PURPOSE: Strength athletes often employ the deadlift in their training or rehabilitation regimens. The purpose of this study was to compare muscle activity between sumo and conventional style deadlifts, and between belt and no-belt conditions. METHODS: Six cameras collected 60-Hz video data and 960-Hz electromyographic data from 13 collegiate football players who performed sumo and conventional deadlifts with and without a lifting belt, employing a 12-RM intensity. Variables measured were knee angles and EMG measurements from 16 muscles. Muscle activity were averaged and compared within three 30-degree knee angle intervals from 90 to 0 degrees during the ascent, and three 30-degree knee angle intervals from 0 to 90 degrees during the descent. RESULTS: Overall EMG activity from the vastus medialis, vastus lateralis, and tibialis anterior were significantly greater in the sumo deadlift, whereas overall EMG activity from the medial gastrocnemius was significantly greater in the conventional deadlift. Compared with the no-belt condition, the belt condition produced significantly greater rectus abdominis activity and significantly less external oblique activity. For most muscles, EMG activity was significantly greater in the knee extending intervals compared with the corresponding knee flexing intervals. Quadriceps, tibialis anterior, hip adductor, gluteus maximus, L3 and T12 paraspinal, and middle trapezius activity were significantly greater in higher knee flexion intervals compared with lower knee flexion intervals, whereas hamstrings, gastrocnemius, and upper trapezius activity were greater in lower knee flexion intervals compared with higher knee flexion intervals. CONCLUSIONS: Athletes may choose to employ either the sumo or conventional deadlift style, depending on which muscles are considered most important according to their training protocols. Moderate to high co-contractions from the quadriceps, hamstrings, and gastrocnemius imply that the deadlift may be an effective closed kinetic chain exercise for strength athletes to employ during knee rehabilitation.

PMID: 11932579 [PubMed - indexed for MEDLINE]

: Kinematics and kinetics of the dead lift in adolescent power lifters.

Brown EW, Abani K.

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.

PMID: 4068962 [PubMed - indexed for MEDLINE]

5: Med Sci Sports Exerc. 1991 Oct;23(10):1179-86.

Muscle fiber characteristics of competitive power lifters.

Fry AC, Webber JM, Weiss LW, Harber MP, Vaczi M, Pattison NA.

Human Performance Laboratories, The University of Memphis, Memphis, Tennessee 38152, USA. afry@memphis.edu

To examine the skeletal muscle characteristics of power lifters, 5 competitive power lifters (PL; X +/- SE; age = 31.0 +/- 1.5 years, squat = 287.7 +/- 15.7 kg, bench press = 170.5 +/- 17.7 kg, and deadlift = 284.2 +/- 7.5 kg) and 5 untrained control subjects (CON; age = 27.3 +/- 3.3 years) served as subjects. Isokinetic squat force and power was greater (p < 0.05) for the PL at all bar velocities (0.20, 0.82, and 1.43 m;pd s(-1)), as was vertical jump height and estimated power. Muscle biopsies from the vastus lateralis m. revealed significant differences for percent fiber type (PL, IIA = 45.5 +/- 1.6%, IIB = 1.3 +/- 0.8%; CON, IIA = 33.4 +/- 3.1%, IIB = 12.0 +/- 2.4%); percent fiber type area (PL, IIA = 51.8 +/- 1.6%, IIB = 1.3 +/- 0.8%; CON, IIA = 43.5 +/- 3.4%, IIB = 12.4 +/- 2.6%); and percent myosin heavy chain isoform (PL, IIa = 59.5 +/- 6.1%; CON, 46.5 +/- 2.5%). Muscle fiber characteristics were significantly correlated (r = +/- 0.61) with numerous strength and power measures for the PL. These data illustrate the muscle fiber characteristics necessary for the maximal force production requirements of power lifting.

Publication Types:

PMID: 12741885 [PubMed - indexed for MEDLINE]

: Considering body mass differences, who are the world's strongest women?

Vanderburgh PM, Dooman C.

Health and Sport Science Dept., University of Dayton, OH 45469-1210, USA. vanderbu@yar.udayton.edu

PURPOSE: Allometric modeling (AM) has been used to determine the world's strongest body mass-adjusted man. Recently, however, AM was shown to demonstrate body mass bias in elite Olympic weightlifting performance. A second order polynomial (2OP) provided a better fit than AM with no body mass bias for men and women. The purpose of this study was to apply both AM and 2OP models to women's world powerlifting records (more a function of pure strength and less power than Olympic lifts) to determine the optimal model approach as well as the strongest body mass-adjusted woman in each event. METHODS: Subjects were the 36 (9 per event) current women world record holders (as of Nov., 1997) for bench press (BP), deadlift (DL), squat (SQ), and total (TOT) lift (BP + DL + SQ) according to the International Powerlifting Federation (IPF). RESULTS: The 2OP model demonstrated the superior fit and no body mass bias as indicated by the coefficient of variation and residuals scatterplot inspection, respectively, for DL, SQ, and TOT. The AM for these three lifts, however, showed favorable bias toward the middle weight classes. The 2OP and AM yielded an essentially identical fit for BP. CONCLUSIONS: Although body mass-adjusted world records were dependent on the model used, Carrie Boudreau (U.S., 56-kg weight class), who received top scores in TOT and DL with both models, is arguably the world's strongest woman overall. Furthermore, although the 2OP model provides a better fit than AM for this elite population, a case can still be made for AM use, particularly in light of theoretical superiority.

PMID: 10647549 [PubMed - indexed for MEDLINE]

: Validation of the Wilks powerlifting formula.

Vanderburgh PM, Batterham AM.

Department of Health and Sport Science, University of Dayton, OH 45469-1210, USA. vanderbu@yar.udayton.edu

PURPOSE: Because maximal strength varies with body mass, the International Powerlifting Federation (IPF) has adopted a method of adjusting powerlifting events (bench press, BP; squat, SQ; deadlift, DL, and total lift (the sum of BP, DL, and SQ), TOT) by body mass. This method, the Wilks formula, multiplies one's lift by an index based on body mass so that lifters of different size can be compared on the same event. The Wilks formula is not, however, based on published data and has yet to be critically evaluated. The purpose of this investigation, then, was to validate the Wilks formula. METHODS: This was performed by 1) examining residuals bias to verify that the adjusted score does, in fact, lead to no systematic bias based on body mass and 2) by applying a more theoretically supportable allometric model to the same data and comparing the fit with the Wilks approach. Subjects were the current men's and women's world record holders as well as the top two performers for each event in the IPF's 1996 and 1997 World Championships (a total of 30 men and 27 women for each lift). RESULTS: Results of data analysis regarding the Wilks formula indicate that: 1) there is no bias for men's or women's BP and TOT; 2) there is a favorable bias toward intermediate weight class lifters in the women's SQ with no bias for men's SQ; and 3) there is a linear unfavorable bias toward heavier men and women in the DL. Furthermore, the allometric approach indicated a bias against light and heavy men and women which may be considered acceptable given that half as many lifters are found in the lightest and heaviest weight classes as in the intermediate weight classes. CONCLUSION: As used currently (BP and TOT only), the Wilks formula appears to be a valid method to adjust powerlifting scores by body mass.

PMID: 10613442 [PubMed - indexed for MEDLINE]

: Prediction of the oxygen cost of the deadlift exercise.

Brown SP, Clemons JM, He Q, Liu S.

Department of Exercise Science and Leisure Management, University of Mississippi, University 38677.

The purpose of this study was to examine the relationship between total estimated work, bar load and total oxygen consumption (TVO2) during the deadlift exercise. Forty-two observations of TVO2 during a wide range of deadlifting bouts were made on a heterogeneous sample of 10 males and 14 females. TVO2 was measured by standard open-circuit spirometry. An R of 0.912 for work and TVO2 indicated that total estimated work during deadlifting can be used to predict oxygen cost accurately. The calculated regression equation was TVO2 (litres of O2) = 2.63 + 0.80 work (kJ) with a S.E.E. of 1.50 litres O2. An R of 0.909 for bar load and TVO2 indicated essentially the same predictability using bar load as the independent variable. The calculated regression equation was TVO2 (litres O2) = 2.88 + 0.005 bar load (kg) with a S.E.E. of 1.5 litres O2. Care should be taken when converting oxygen cost to energy expenditure values using non-protein R equivalents, since underestimations are likely, due to the heavy glycolytic involvement.

PMID: 7932947 [PubMed - indexed for MEDLINE]

: Continuous measurement of left ventricular performance during and after maximal isometric deadlift exercise.

Sullivan J, Hanson P, Rahko PS, Folts JD.

Department of Medicine, University of Wisconsin Medical School, Madison.

BACKGROUND. Isometric exercise produces a reflex increase in arterial blood pressure that is proportional to the intensity and mass of muscle used during contraction. Little is known about the transient effects of heavy weight lifting on left ventricular performance. In this study, we measured continuous changes in left ventricular performance during maximal large-muscle isometric exercise using the standing deadlift position. METHODS AND RESULTS. Ten healthy young men performed serial deadlifts at 50% of maximal voluntary effort for 90 seconds and 100% of maximal effort for 30 seconds. Echocardiographic imaging (apical four-chamber view), arterial blood pressure (brachial artery catheter), and electrocardiographic monitoring were recorded throughout the deadlift and for 30 seconds of recovery. Aortic flow velocity was also monitored during a separate series of deadlifts. During 100% maximal deadlift, mean arterial pressure increased from 108 +/- 4 to 164 +/- 6 mm Hg. Left ventricular ejection fraction declined initially (from 57 +/- 2% to 49 +/- 3%) at 15 seconds into the lift and recovered (56 +/- 1%) due to significant increases in end-diastolic volume (104 +/- 11 ml to 132 +/- 16 ml) by the end of the lift. The peak systolic pressure/end-systolic volume ratio did not change during the deadlift. After cessation of the deadlift, mean arterial pressure declined precipitously (to 88 +/- 4 mm Hg) within 5 seconds and gradually returned to baseline after 30 seconds. Left ventricular performance indexes all increased significantly during the recovery phase (ejection fraction to 68 +/- 3%, peak systolic pressure/end-systolic volume ratio to 5.9 +/- 0.9). Findings were qualitatively similar for the 50% deadlift. CONCLUSIONS. During an intense isometric deadlift, left ventricular performance declines initially but is restored by the Frank-Starling mechanism. Upon release of the deadlift, increased left ventricular performance develops in conjunction with a rapid decrease in arterial pressure. The combined effects of increased wall stress during the lift phase and enhanced contractility during the release phase probably contribute to left ventricular hypertrophy associated with repetitive weight training.

PMID: 1555283 [PubMed - indexed for MEDLINE]

: Left ventricular responses to upright isometric handgrip and deadlift in men with coronary artery disease.

Sagiv M, Hanson P, Besozzi M, Nagle F.

Isometric exercise is usually discouraged for patients with coronary artery disease (CAD) because of the possible adverse effects of increased blood pressure on left ventricular (LV) function. Cardiovascular and LV responses to upright handgrip and deadlift were compared in 10 normal men (mean age 52 years) and 14 men (mean age 54 years) with documented CAD or myocardial infarction who were in a supervised exercise program. Handgrip and deadlift were each performed at 30% maximal effort for 3 minutes. LV technetium-99m multigated radionuclide angiograms, electrocardiogram and blood pressure were measured during the final 60 seconds. CAD patients had a significantly lower LV ejection fraction at rest (41%) than normal subjects (57%). Both groups showed equal and significant increases in heart rate, systolic and diastolic pressure during handgrip and deadlift. These responses were all significantly greater in both groups during deadlift. No significant changes in LV ejection fraction occurred in either group during handgrip or deadlift. LV wall motion abnormalities were present in 9 of 14 CAD patients at rest and increased with handgrip (11 men) and deadlift (13 men). No LV abnormalities occurred in normal subjects. These data indicate cardiovascular responses are similar in normal and exercise-trained CAD patients during upright submaximal isometric exercise using small or large muscle groups. Radionuclide measurements of global LV function remain stable in both groups, during similar conditions of increased systolic pressure afterload. However, LV wall motion abnormalities are aggravated in CAD patients during isometric exercise.

PMID: 3993560 [PubMed - indexed for MEDLINE]