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Medicine amp Science in Sports amp Exercise

Issue Volume 28(2) February 1996 pp 218-224

Copyright copy1996The American College of Sports Medicine

Publication Type [Applied Sciences Biodynamics]

ISSN 0195-9131

Accession 00005768-199602000-00010

Keywords WEIGHTLIFTING POWERLIFTING SQUATTING EXERCISE HIP KNEE EMG BIOMECHANICS

High- and low-bar squatting techniques during weight-training

WRETENBERG PER FENG YI ARBORELIUS ULF P

Author InformationKinesiology Research Group Department of Neuroscience Karolinska Institute S-171 77 Stockholm SWEDEN

Submitted for publication December 1993

Accepted for publication October 1994

Address for correspondence Per Wretenberg Kinesiology Research Group Department of Neuroscience Karolinska Institute S-171 77

Stockholm Sweden

ABSTRACT

Eight Swedish national class weightlifters performed ldquohigh-barrdquo squats and six national

class powerlifters performed ldquolow-barrdquo squats with a barbell weight of 65 of their 1 RM

and to parallel- and a deep-squatting depth Ground reaction forces were measured with a

Kistler piezo-electric force platform and motion was analyzed from a video record of the

squats A computer program based on free-body mechanics was designed to calculate

moments of force about the hip and knee joints EMG from vastus lateralis rectus femoris

and biceps femoris was recorded and normalized The peak moments of force were flexing

both for the hip and the knee The mean peak moments of force at the hip were for the

weightlifters 230 Nm (deep) and 216 Nm (parallel) and for the powerlifters 324 Nm (deep)

and 309 Nm(parallel) At the knee the mean peak moments for the weightlifters were 191

Nm (deep) and 131 Nm (parallel) and for the powerlifters 139 Nm (deep) and 92 Nm

(parallel) The weightlifters had the load more equally distributed between hip and knee

whereas the powerlifters put relatively more load on the hip joint The thigh muscular activity

was slightly higher for the powerlifters

The squatting exercise performing a knee bend while carrying a weight on the shoulders

is an often used and important method for hip knee and back muscle training (3182223)

Many athletes in different disciplines use this type of exercise as the basic exercise to

strengthen the leg muscles and the method is considered supreme for this purpose by many

coaches (429) Weightlifters and powerlifters use squatting as one of the most important

parts of their training programs and for the powerlifters this kind of squatting is directly

included during their competition performance (131415) In the weightlifting competition

the back squat is not directly included rather the front-squat with the barbell on the chest

still the back-squat training is important also for the weightlifters

The squatting exercise can be performed in different ways The weights on the shoulders

and numbers of repetitions can vary depending on the purpose Squatting depth is another

important factor and the parallel and deep squat dominates During the parallel squat the

knees are flexed until the posterior borders of the hamstrings muscles are parallel to the

floor whereas during the deep squat the knees are maximally flexed In a previous study

(32) we showed that the quadriceps muscle activity is the same for these two different types

of squats but that the load on the knee joints is larger for the deep squat

of squats but that the load on the knee joints is larger for the deep squat

There are two main techniques for the squatting exercise with the bar on the back the

ldquohigh-barrdquo squat and the ldquolow-barrdquo squat (29) The names of the techniques are related to

the placement of the bar on the back The bar is either centered across the shoulders just

below the spinous process of the C7 vertebraldquohigh-barrdquo or further down on the back across

the spine of the scapula ldquolow-barrdquo It has been shown that the low-bar squat is characterized

by more forward lean of the trunk (12) and that powerlifters use the low-bar squatting

technique since this enables them to lift heavier loads (29) The weightlifters mainly use the

high-bar technique which more simulates the movement during their snatch and clean and

jerk competition During competition the weightlifters use the front-squat movement which

is done in an upright position since they cannot balance the weight with too much forward

lean of the trunk Athletes other than lifters may use techniques that are not strictly defined

It is known that injury may occur by overloading the knee joint (1) and also that

squatting generates high forces which can result in serious injuries (1628) During the jerk

dip in weightlifting competition with its large acceleration serious injuries also have occurred

(33) Whether there is a difference in loading moments of force on the hip and knee between

the high- and low-bar squat is however not known but this is of interest eg when

planning the training after an injury In this study we analyze how high- and low-bar squats

effect hip and knee load and the thigh muscle activity Studies such as this offer one way of

improving our knowledge of the biomechanical effects of different training methods

METHOD

Subjects

Eight weightlifters and six powerlifters all of Swedish national class in their age and

bodyweight categories participated in the study Written informed consent was obtained

from the subjects The mean age of the weightlifters was 19 yr (SD plusmn 3) and their mean

weight was 82 kg (SDplusmn 11) The mean age of the powerlifters was 31 yr (SD plusmn 3) and their

mean weight was 87 kg (SD plusmn 20) (Table 1) One of the weightlifters had pain in the knees

due to previous overstrain but he felt it did not affect the way he performed the squat with

the moderate weights used in this study All other lifters were without dysfunction in the

locomotor system

TABLE 1 Subject data 1 RM is the subjects one-repetition maximum for the deep squat

Procedure

The weightlifters performed high-bar squats and the powerlifters performed low-bar

squats We did not let all lifters do both high- and low-bar squats since by testing some of the

lifters we realized that they could not perform the type of squat they were not used to in an

optimal way Two different types of squatting depths were also studied the parallel squat and

the deep squat During the parallel squat the knees were flexed until the posterior borders of

the hamstrings muscles were parallel to the floor and during the deep squat the knees were

maximally flexed Before starting the parallel squat the appropriate squatting depth was

indicated with a non-weight-bearing stop bar beneath the subjects buttocks During the

indicated with a non-weight-bearing stop bar beneath the subjects buttocks During the

movement the subjects flexed their knees until contact was made with the bar All

movements were performed on a force plate (60 times 30 cm) where the feet were placed

symmetrically They could freely choose their stance with and no subject felt restricted by

the 60-cm width of the force plate The bar weight was individually based on the subjects all

time one-repetition maximum (1 RM) for a deep squat exercise as reported by the subjects

A weight of 65 of the 1 RM was chosen None of the lifters wore wraps or belts since this

could have effects on the calculation of the moment of force and since it has been shown that

belts can decrease the electromyographic activity during squatting (20) One of the

weightlifters performing a deep squat is shown in Figure 1

Figure 1-Weightlifter performing a deep squat high-bar technique

For motion analyses a video camera (Panasonic MS1 frame rate 25 Hz with high speed

shutter 11000) and a video recorder (Panasonic 8500) were used The camera was placed to

the left of all subjects at a focal distance of 8 m For synchronization of the force recordings

and the video the computer was triggered by an optical time indication panel visible on the

video recording Skin markers were placed at five places on the body trunk (mid-axillar line

at umbilicus height) hip (superior part of greater trochanter) knee (lateral epicondyle)

ankle (lateral malleolus) and foot (head of fifth metatarsal) The coordinates for these

markers were extracted frame-by-frame from the video recordings with a video position

analyzer (FOR-A company VPA 1000)

The ground reaction forces on the feet were measured with a Kistler multi-component

piezoelectric platform (type 9281 B) which measured the vertical anteroposterior and

piezoelectric platform (type 9281 B) which measured the vertical anteroposterior and

lateral ground reaction forces during rising All force signals (sampled at 100 Hz) were

channelled through Kistler amplifying units (type 5006) to a microcomputer (Luxor ABC 800)

where they were AD converted and stored The position of the center of pressure of the

reaction force between the feet and the ground was also obtained from the force plate

Combining these data with the video coordinates gave the appropriate sagittal moment arms

with respect to the hip and knee joint markers Dempsters anthropometrical data (6) were

used to determine the segmental masses and their mass center locations

A computer program based on free-body mechanics was designed to calculate the

moments of force about the hip (superior part of greater trochanter) and knee (center of

lateral epicondyle) by multiplying each external force (body segment weight or horizontal or

vertical reaction force) by its moment arm length (Fig 2) A ldquosemidynamicrdquo method was

used which incorporated ground reaction forces measured from a force plate and

gravitational contributions from body segments Semidynamic methods have proved to give

results very close to calculation with fully dynamic methods (21) McLaughlin et al (23) and

Lander et al (19) have also analyzed torques and joint forces for squat movements with both

dynamic and semidynamic methods and they found only minor differences indicating that

this kind of method is adequate for these calculations These studies show that the inertial

forces are low compared with the ground reaction forces Similar methods for calculation of

moment of force have been used earlier (5926) and this particular system has been used in

several investigations (eg 31) The same type of technique has also been used in similar

weightlifting studies (210) but fully dynamic methods also are used in weightlifting studies

(11) The patellofemoral compressive force during the parallel squat was calculated using our

moment of force data and diagrams previously published by Nisell and Ekholm (27)

Figure 2-Calculation of the moment of force about the hip(MH) RX and RY are the

horizontal and vertical components of the reaction force from the force plate WT WS

and WF are the segmental weights of thigh shank and foot (XH YH) are the X and Y

cordinates for the marker on the hip joint(XT YT) (XS YS) and (XF YF) are the X and

Y coordinates for the center of gravity of the thigh shank and foot XR and YR are the X

and Y coordinates of the application point of the reaction force

The activity in the vastus lateralis rectus femoris and the long head of the biceps

femoris muscles was recorded (Devices M4 AC8) by means of full-wave rectified low-pass-

filtered and time-averaged electromyogram (linear envelope EMG) The low-pass time

constant was 100 ms Surface (AgAgCl) electrodes were placed on the skin over the muscles

in the fibers direction with an inter-electrode distance of 2 cm For control of artifacts

direct EMG was visualized in parallel on an oscilloscope (Tektronix RM565)

To quantify the muscular activity and to compare the activity between different squats

the EMG activity during the movements was related to a static reference action As reference

contraction a parallel squat with a barbell weight of 65 of 1 RM was chosen The peak EMG

value during a 3-s static parallel position was used as the reference value The muscular

activity is expressed as a quotient of the reference value Normalization like this has been

used earlier (7817)

Statistics

Since the data were approximately normally distributed and since this type of data in

general is known to be normally distributed the parametrict test was used for the statistical

analysis Comparison was done between parallel and deep squats within each group and

between powerlifters and weightlifters for the parallel and deep squat respectively For the

comparison between weightlifters and powerlifters one has to be aware of the differences in

groups concerning body weights and lifted weights

RESULTS

Moments of Force

The joint moment of force curves for one weightlifter and one powerlifter are shown in

Figure 3 All flexing loading moments of force are expressed as positive which means that

the curves describe mainly flexing loading moments for both the hip and the knee These

flexing moments are counteracted by the extensor muscles producing extending moments on

the hip and knee joints The calculated moments are the net muscular moments the effects

of antagonistic muscular activity are not considered The distinct peaks on the curves

correspond to the turning point during the change from knee flexion to knee extension The

two lifters have different load distributions The powerlifter put relatively more load on the

hip joint than on the knee joint while the weightlifter had a more equal distribution of load

between hip and knee

Figure 3-Individual moment curves for one weightlifter and one powerlifter performing a

deep squat Flexing loading moment of force are expressed as positive

Figure 4 shows the mean maximum moments of force for the hip and knee joints for the

different lifters during both the parallel squat and the deep squat Also the mean moment

data show that the weightlifters have a more equal load distribution between hip and knee

than the powerlifters The mean maximum moment at the hip joint was for the powerlifters

324 Nm (deep) and 309 Nm (parallel) The corresponding values for the weightlifters were 230

Nm (deep) and 216 Nm (parallel) The powerlifters had a significantly higher hip moment of

force both for the parallel and deep squat (P lt 005) The differences between the parallel

and the deep squats within each group were not significant At the knee joint there was a

different situation Although the powerlifters were heavier and lifted heavier loads than the

weightlifters they showed the lowest moment of force both for the parallel and the deep

squats and the difference was significant(P lt 005) for the parallel squat The mean

maximum moments were for the powerlifters 139 Nm (deep) and 92 Nm (parallel) For the

weightlifters the mean maximum flexing knee moments were 191 Nm (deep) and 131 Nm

(parallel) Independent of technique the load on the knees increased significantly with

increasing squatting depth (P lt 0005)

Figure 4-Mean maximum moment of force with 95 confidence interval on the hip and

knee joints for the weightlifters and powerlifters during parallel squat and deep squat

(WE N = 8 PON = 6)

The weightlifters showed positive correlation between hip load and the total mass of lifter

and barbell The strongest correlation was found for the deep squat (r = 092) but the

correlation was also significant for the parallel squat (r = 088 P lt 001) There was also a

tendency to positive correlation between hip load and total mass for the powerlifters both for

the parallel (r = 075) and the deep (r = 076) squat but with only six lifters the correlation

was not significant The corresponding values for the knee joint showed that the moments of

force did not increase proportionally with external load This has been found earlier for world

class weightlifters (2)

Knee Forces

We thought it would be interesting to calculate one force component in the knee that

would reflect the magnitudes of the forces in the knee during squatting Therefore the

patello-femoral compression force for the parallel squat was calculated The mean peak

compression force for the weightlifters was 4700 N (SD plusmn 590) and for the powerlifters 3300 N

(SD plusmn 1700) (26)

Electromyography

The muscular activity in the vastus lateralis the rectus femoris and the biceps femoris

muscles was recorded and the mean muscular activity peaks with 95 confidence intervals

are shown in Figure 5 For all muscles and both the parallel and the deep squat the mean peak

muscular activity was higher for the powerlifters However in this study with six powerlifters

and eight weightlifters a significant difference was found only for the rectus femoris muscle

(P lt 005) The highest activity levels both for the weightlifters and the powerlifters were

found for the biceps femoris muscle with a relative muscular activity of about three times

the reference level However the activity in this muscle also showed the greatest individual

difference

Figure 5-Mean maximum muscular activity for the three muscles studied with 95

confidence interval 10 corresponds to the activity during the static reference

contraction (WE N = 8 PON = 6)

Movement and Joint Angles

The knee flexion angles were slightly smaller for the powerlifters The mean knee flexion

angle for the powerlifters were 111deg (SD plusmn 5) for the parallel and 126deg (SD plusmn 4) for the deep

squat The corresponding angles for the weightlifters was 116deg (SD plusmn 5) for the parallel and

138deg (SD plusmn 3) for the deep squat Analyses of the hip flexion angles show that both the

weightlifters and the powerlifters increased these angles with increasing squating depth The

mean maximal hip flexion angles for the weightlifters was 111deg (SD plusmn 8) during the parallel

squat and 125deg (SD plusmn 4) during the deep squat The corresponding angles for the power lifters

were 132deg (SD plusmn 4) and 146deg (SD plusmn 3) respectively By flexing the hip more the powerlifters

leaned the trunk farther forward (Fig 6)

Figure 6-Schematic drawing of the lowest position during the parallel squat A)

weightlifter B) powerlifter Measured angles are indicated the horizontal line indicates

the position of the thigh

DISCUSSION

Since squatting exercise is an important part of the strength training for many athletes

it is important to understand the effects of different squatting techniques In this study we

used weightlifters and powerlifters to demonstrate effects of the high- and low-bar squats

We are aware that there is a difference in age between the two lifter categories but the

analysis showed no difference in principle muscular activity or load between the oldest and

youngest lifters in each group

The study shows the differences between the high- and low-bar techniques and also the

effects on the hip and knee moment of force The low-bar squat with the barbell further

down on the back is characterized of a larger hip flexion (Fig 6) and this technique creates a

hip moment of force that in Newton-meter is almost twice as large as the knee moment The

high-bar squat however is performed more upright and the joint moment of force are more

equally distributed between the hip and knee joints The hip and knee angles in the present

study correlate well with the angles found by Fry et al (12) and confirm the more upright

position during the high-bar squat Although the powerlifters were larger and lifted heavier

loads than the weightlifters the mean moment of force on the knee joint was lower than for

the weightlifter and the difference was significant for the parallel squat The powerlifters

however had significantly a higher load on the hip joint compared with the weightlifters The

difference in hip load could be an effect of heavier lifters lifting heavier loads in addition to

an effect of different technique but the difference in knee moment of force could hardly be

explained from anything else but different lifting technique It is clear that weightlifter

coaches want the squat to be done as upright as possible This is the only way to approach the

movement during weightlifting competition Powerlifting coaches however want lifters to lift

as much as possible with hip and back since by experience they know that this enables the

lifter to lift heavier loads The calculated moment of force on the joint is dependent on the

size of the ground reaction force and the distance between this force and the joint center

the moment arm By increasing hip flexion the powerlifters manage to balance the weight

closer to the knee and thereby reduce the moment arm The moment arm between the

ground reaction force and the hip joint however will increase creating a higher moment of

force on this joint The high-bar squat is performed in a more balanced way where both the

barbell and the trunk center of gravity are centered between hip and knee and thereby the

moments of force are more equally distributed

The powerlifters showed higher EMG activity than the weightlifters for all investigated

muscles although the difference was significant only for the rectus femoris The powerlifters

were heavier and lifted heavier loads but this could be the explanation to the higher muscular

activity EMG activity however was normalized in relation to a reference contraction with

the same relative external load which might indicate that the low-bar squat actually is

advantageous from a muscular recruitment point of view It is clear however that

weightlifters must train with a technique close to the competition situation which means the

high-bar squat Some other athletes might benefit from using a technique close to the low-bar

squat providing that they have the low back strength to safely perform a low bar squat

It is a little surprising that powerlifters performing low-bar squats with relatively low

moment of force at the knee joints have a knee extensor muscular activity even slightly

higher than weightlifters performing high-bar squats with higher knee moments The

explanation must be that the moments calculated are net loading moments of force which

means that muscular co-contraction is not included in the values calculated The activity in the

biceps femoris muscle is slightly higher for the low-bar squat The activity in the

gastrocnemius muscle and the soleus muscle was not recorded However since the low-bar

squat is performed with the total center of gravity further forward the need for

compensatory ankle plantar flexion will increase which means increased activity in both the

gastrocnemius and the soleus muscles During the low-bar squat knee flexor muscle activity

increases and hereby knee extensor co-contraction This can explain why the knee extensor

activity is high despite the relatively low net knee loading moment As previously mentioned

one should be aware that the calculated moments are net moments of force and that the

effect of co-contracting antagonistic muscles are not taken into account A antagonistic

moment of force created by the antagonist would increase the moment of force produced by

the agonists Therefore the moment calculated in this study must be taken as minimum

loading moments for the agonists Two joint muscles can in this way serve as agonist at one

of the joints and antagonists at an other The biceps femoris for example produce an

extending moment of force at the hip but an antagonistic flexing moment of force at the

knee The magnitude of this antagonistic moment is not possible to calculate in a study like

this

Although hip extensor activity was not analyzed it seems logical that the low-bar squat

should be the best technique concerning hip extensor training since this technique create the

greatest moments of force at the joint

The patello-femoral compression force was calculated to give an apprehension of the

force magnitudes Forces in the hip and knee depend not only on the moment of force but

also on joint angle (222425) For a constant moment of force joint compression forces

increase with increasing flexion angle This has been investigated for hip flexion up to 90deg and

for knee flexion up to 120deg For the knee the patello-femoral compression force levels away

between 90 and 120deg So the reason for larger compression force in the knee for the

weightliftres was not because of a larger knee flexion angles rather related to the larger

moment of force

Both the weightlifters and powerlifters have a strict and precise squatting technique It is

probable that many other athletes in other disciplines use techniques in between the high- and

low-bar techniques and that their coaches are not aware of the effects of the different

techniques Athletes should benefit from studying lifters and their technique and the different

effects that can be achieved It is known that squatting exercise is a good method for knee

rehabilitation training (30) and we suggest that after a hip injury high-bar squat should be

used at the beginning to minimize the risk of hip overload After a knee injury a squatting

technique more similar to the low-bar technique should be preferred Further investigation

on for example shear and compression forces on the lumbar spine during the two different

types of squatting technique must be important to prevent reinjury of the lower back during

rehabilitation exercise

REFERENCES

1 Ariel B G Biomechanical analysis of the knee joint during deep knee bends with heavy

load In Biomechanics IV A J Nelson and C A Morehouse (Eds) Baltimore University

Park Press 1975 pp 44-52 [Context Link]

2 Baumann W V Gross K Quade P Galbierz and A Schwirtz The snatch technique of

world class weightlifters at the 1985 world championships Int J Sprots Biomech 468-89

1988 [Context Link]

3 Chandler T J and M H Stone The squat exercise in athletic conditioning a review of

the literature Natl Strength Condit Assoc J 1352-58 1991 [Context Link]

4 Coaches Roundtable The squat and its application to athletic performance Natl Strength

Condit Assoc J 610-22 1984 [Context Link]

5 Dahlkvist N J P Mayo and B B Seedhom Forces during squatting and rising from a

deep squat Eng Med 269-76 1982 [Context Link]

6 Dempster W T and G R L Gaughran Properties of body segments based on size and

weight Am J Anat 12033-54 1967 [Context Link]

7 Ekholm J R Nisell U P Arborelius C Hammarberg and G Nemeth Load on knee

joint structures and muscular activity during lifting Scand J Rehabil Med 161-9 1984

Bibliographic Links [Context Link]

8 Ekholm J R Nisell U P Arborelius O Svensson and G Nemeth Load on knee joint

and knee muscular activity during machine milking Ergonomics 4665-682 1985

Bibliographic Links [Context Link]

9 Ellis M I B B Seedhom A A Amis D Dowson and V Wright Forces in the knee joint

whilst rising from normal and motorized chairs Eng Med 133-40 1979 [Context Link]

10 Enoka R M The pull in Olympic weightliftingMed Sci Sports 2131-137 1979 [Context

Link]

11 Enoka R M Load- and skill-related changes in segmental contributions to a weightlifting

movement Med Sci Sports Exerc 2178-187 1988 [Context Link]

12 Fry A C T A Aro J A Bauer and W J Kraemer A comparison of methods for

determining kinematic properties of three barbell squat exercises J Hum Mov Stud 2483-

95 1993 [Context Link]

13 Garhammer J Performance evaluation of Olympic weightlifters Med Sci Sports 3284-

287 1979 [Context Link]

14 Garhammer J Power production by olympic weightlifters Med Sci Sports Exerc 154-

60 1980 [Context Link]

15 Garhammer J Biomechanical profiles of olympic weightlifters Int J Sports Biomech

1122-130 1985 [Context Link]

16 Grenier R and A Guimont Simultaneous bilateral rupture of the quadriceps tendon and

leg fractures in a weightlifterAm J Sports Med 6451-453 1983 Bibliographic Links

[Context Link]

3 Chandler T J and M H Stone The squat exercise in athletic conditioning a review of

the literature Natl Strength Condit Assoc J 1352-58 1991 [Context Link]

4 Coaches Roundtable The squat and its application to athletic performance Natl Strength

Condit Assoc J 610-22 1984 [Context Link]

5 Dahlkvist N J P Mayo and B B Seedhom Forces during squatting and rising from a

deep squat Eng Med 269-76 1982 [Context Link]

6 Dempster W T and G R L Gaughran Properties of body segments based on size and

weight Am J Anat 12033-54 1967 [Context Link]

7 Ekholm J R Nisell U P Arborelius C Hammarberg and G Nemeth Load on knee

joint structures and muscular activity during lifting Scand J Rehabil Med 161-9 1984

Bibliographic Links [Context Link]

8 Ekholm J R Nisell U P Arborelius O Svensson and G Nemeth Load on knee joint

and knee muscular activity during machine milking Ergonomics 4665-682 1985

Bibliographic Links [Context Link]

9 Ellis M I B B Seedhom A A Amis D Dowson and V Wright Forces in the knee joint

whilst rising from normal and motorized chairs Eng Med 133-40 1979 [Context Link]

10 Enoka R M The pull in Olympic weightliftingMed Sci Sports 2131-137 1979 [Context

Link]

11 Enoka R M Load- and skill-related changes in segmental contributions to a weightlifting

movement Med Sci Sports Exerc 2178-187 1988 [Context Link]

12 Fry A C T A Aro J A Bauer and W J Kraemer A comparison of methods for

determining kinematic properties of three barbell squat exercises J Hum Mov Stud 2483-

95 1993 [Context Link]

13 Garhammer J Performance evaluation of Olympic weightlifters Med Sci Sports 3284-

287 1979 [Context Link]

14 Garhammer J Power production by olympic weightlifters Med Sci Sports Exerc 154-

60 1980 [Context Link]

15 Garhammer J Biomechanical profiles of olympic weightlifters Int J Sports Biomech

1122-130 1985 [Context Link]

16 Grenier R and A Guimont Simultaneous bilateral rupture of the quadriceps tendon and

leg fractures in a weightlifterAm J Sports Med 6451-453 1983 Bibliographic Links

[Context Link]

[Context Link]

17 Hammarskjoumlld E K Harms-Ringdahl and J Ekholm Shoulder-arm muscular activity and

reproducibility in carpenters work Clin Biomech 581-87 1990 Bibliographic Links

[Context Link]

18 Hattin H C M R Pierrynowski and K A Ball Effect of load cadence and fatigue on

tibio-femoral joint force during a half squat Med Sci Sports Exerc 5613-618 1989

[Context Link]

19 Lander J F R L Simonton and J K F Giacobbe The effectiveness of weight-belts

during the squat exercise Med Sci Sports Exerc 22117-126 1990 Ovid Full Text

Bibliographic Links [Context Link]

20 Lander J E J R Hundley and R L Simonton The effectiveness of weight-belts

during multiple repetitions of the squat exercise Med Sci Sports Exerc 24603-609 1992

Ovid Full Text Bibliographic Links [Context Link]

21 Lindbeck L and U P Arborelius Inertial effects from single body segments in dynamic

analysis of lifting Ergonomics 4421-433 1991 Bibliographic Links [Context Link]

22 McLaughlin T M C J Dillman and T J Lardner A kinematic model of performance in

the parallel squat by champion powerliftersMed Sci Sports 2128-133 1977 [Context Link]

23 McLaughlin T M T J Lardner and C J Dillman Kinetics of the parallel squat Res Q

2175-189 1978 [Context Link]

24 Nemeth G and J Ekholm A biomechanical analysis of hip compression loading during

lifting Ergonomics 28429-440 1985 Bibliographic Links [Context Link]

25 Nemeth G J Ekholm and U P Arborelius Hip load moments and muscular activity

during lifting Scand J Rehabil Med 16103-111 1984 Bibliographic Links [Context Link]

26 Nemeth G J Ekholm U P Arborelius K Schlt951gtuldt and K Harms-Ringdahl Hip

joint load and muscular activation during rising exercises Scand J Rehabil Med 1693-102

1984 Bibliographic Links [Context Link]

27 Nisell R and J Ekholm Patellar forces during knee extension Scand J Rehabil Med

1763-74 1985 Bibliographic Links [Context Link]

28 Nisell R and J Ekholm Joint load during the parallel squat in powerlifting and forces of

in vivo bilateral quadriceps tendon rupture Scand J Sports Sci 863-70 1986 [Context

Link]

29 OShea P The parallel squat Natl Strength Condit Assoc J 74-6 1985 [Context

Select All Export Selected to PowerPoint

29 OShea P The parallel squat Natl Strength Condit Assoc J 74-6 1985 [Context

Link]

30 Palmitier R A K-N An S G Scott and E Y S Chao Kinetic chain exercise in knee

rehabilitation Sports Med 11402-413 1991 Ovid Full Text Bibliographic Links [Context

Link]

31 Weidenhielm L Knee osteoarthrosis aspects of clinical symptoms corrective surgery leg

alignment and knee joint load(Dissertation) Karolinska Institute Stockholm Sweden 1992

[Context Link]

32 Wretenberg P F Yi F Lindberg and U P Arborelius Joint moment of force and

quadriceps muscle activity during squatting exercise Scand J Med Sci Sports 3244-250

1993 Bibliographic Links [Context Link]

33 Zernicke R F J Garhammer and F W Jobe Human patellar-tendon rupture J

Bone Joint Surg Am A-59179-183 1977 [Context Link]

WEIGHTLIFTING POWERLIFTING SQUATTING EXERCISE HIP KNEE EMG BIOMECHANICS

IMAGE GALLERY

Table 1

Figure 1-Weightlifte

Figure 2-Calculation

Figure 3-Individual

Figure 4-Mean maximu

Figure 5-Mean maximu

Figure 6-Schematic d

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