Isokinetics and Exercise Science 23 (2015) 101–108 101DOI 10.3233/IES-150570IOS Press

Comparison of muscle activation of hip beltsquat and barbell back squat techniques

Dawn T. Gulicka,∗, James A. Fagnanib and Colleen N. GulickcaInstitute for Physical Therapy Education, Widener University, Chester, PA, USAbPhysical Therapy & Wellness Institute, West Norriton, PA, USAcCalifornia State University, Fullerton, CA, USA

Received 14 October 2014

Accepted 14 December 2014

Abstract.BACKGROUND: Hip belt squats are believed to have been introduced in 1970. By removing the load from the shoulders andupper trapezius, the hip belt squat places emphasis on the legs with less load on the spine. No peer-reviewed research exists onthe muscle recruitment patterns of a hip belt squat, or how it compares in muscle activation to other squatting activities.OBJECTIVE: The purpose of the study was to determine lower extremity muscle activation in a hip belt squat (SquatMax =MD) in comparison with a barbell back squat.METHODS: Thirteen participants performed four repetitions of an 8-RM squat using three different techniques: hip belt squatwithout a band, hip belt squat with a band, and barbell back squat. Electromyographic data were collected from six muscles:quadriceps, biceps femoris, hip adductors, hip abductors, gluteus maximus, and gastrocnemius.RESULTS: ANOVA revealed no significant difference in muscle activity between devices. The only muscle group statisticallydifferent between genders was the gastrocnemius (p = 0.04). Hip adductor activity was lowest and hip abductor activity washighest when performing a hip belt squat with the band for both genders. Likewise, the adductor to hamstring ratio was lowestwith the hip belt squat.CONCLUSIONS: Given the lack of significant difference in the muscle activity between the squat techniques, one needs to lookat other attributes to determine both the scientific and, consequently, the practical value. Given the placement of the belt aroundthe pelvis, one positive attribute for the hip belt squat is the ability to unload the shoulders and spine. Another positive attributefor the hip belt squat is the higher hip abductor to adductor ratio. This could be very important for injury prevention and patellatracking. While the back squat has slightly higher hamstring recruitment, which is important in ACL injury prevention, the hipbelt squat may address this by offsetting the free weight with the use of an additional band. If a free weight hip belt squat deviceis available, it may be a better alternative to the traditional barbell squat technique.

Keywords: Back squat, belt squat, muscle recruitment

1. Introduction

Free weight squat is one of the most popular exer-cises used for strength training. It is considered the bestexercise for lower extremity muscle development [1,2].

∗Corresponding author: Dawn T. Gulick, Institute for Physi-cal Therapy Education, Widener University, One University Place,Chester, PA 19013, USA. Tel.: +1 610 499 1287; Fax: +1 610 4991231; E-mail: dtgulick@widener.edu.

Previous research exists on muscle recruitment pat-terns and differences between the squat and other lowerextremity exercises [3–7]. However, no peer-reviewedresearch exists on the muscle recruitment patterns ofa hip belt squat, or how it compares in muscle acti-vation to other squatting activities. Hip belt squats arebelieved to have been introduced in 1970 [8]. Therehave been numerous anecdotal reports of the hip beltsquat being safer than the barbell squat [8–11]. By re-moving the load from the shoulders and upper trapez-

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Table 1Resistance used by device for each participant

Gender Belt squat no band Belt squat with band Back squatAthlete 1 Female 333 267 423Athlete 2 Male 978 800 1157Athlete 3 Male 934 800 1001Athlete 4 Male 934 823 1089Athlete 5 Male 1068 979 1223Athlete 6 Male 823 623 1089Athlete 7 Male 845 756 1045Athlete 8 Male 1068 934 1223Athlete 9 Female 333 267 467Athlete 10 Male 1312 1157 1446Athlete 11 Female 311 222 423Athlete 12 Female 400 333 467Athlete 13 Male 1268 1157 1446∗Note: weights are displayed in Newtons.

ius, the hip belt squat places emphasis on the legs withless load on the spine. This may be important in situa-tions where the athlete has a prior or current shoulderor spine disorder. If one does not have sufficient shoul-der motion to grasp the bar correctly or if additionalload on the spine (i.e. barbell) causes discomfort, a tra-ditional back squat may not be possible. If, however,the same muscular activation can be achieved with analternate technique, the benefits of the squatting mo-tion can be achieved. Thus, the purpose of the studywas to determine lower extremity muscle activation ina hip belt squat (SquatMax = MD) in comparison witha barbell back squat.

2. Methods

2.1. Participants

Thirteen English speaking athletes, 9 men and 4women, over the age of 18 years, who were currentlyinvolved in a strength training program at OverAchieveSports and Speed (King of Prussia, PA) were recruited.Each participant was a competitive athlete who wascompetent with the squat motion on both pieces ofequipment. All participants were capable of perform-ing a squat and their 8-repetition maximum (8-RM)weight for each squat movement was directly deter-mined (Table 1). None of the volunteers had a currentmusculoskeletal injury or any injury/surgery in the past12 months. All participants signed a consent form ap-proved by the university institutional review board forthe protection of human subjects. The study conformedwith the Code of Ethics of the World Medical Associ-ation (Declaration of Helsinki).

Fig. 1. Hip belt squat elastic band configuration on the underside theplatform.

2.2. Equipment

A Chattanooga surface EMG apparatus (DJOGlobal, Vista, CA) was used to monitor muscle activ-ity. A SquatMax-MD hip belt squat platform (King ofPrussia, PA) and barbell back squat rack were used tocompare lifting techniques. Standard disk weights ofvarious increments (11, 22, 44, 111, 155, 200 N) wereused to provide resistance to the lifting techniques. The

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resistance band that was used was a “pro average” bandmade by EliteFTS (London, Ohio). The band set up ofthe hip belt squat is displayed in Fig. 1. In each case,the weight used for the belt squat with the band wasreduced to accommodate the resistance of the band. Asstated by McMaster et al. [12], bands exhibit a curvilin-ear tension-deformation pattern. Thus, any attempt tocalculate a weight to band conversion can result in sig-nificant error [13]. So instead of using a formula, each8-RM for the belt squat with band was directly deter-mined. An 8-RM was selected because the intent of thestudy was to safely examine strength, not endurance.

2.3. Procedures

After informed consent was obtained, anthropomet-ric data was collected (age, height, weight). Each ath-lete was then prepped for electromyographic (EMG)electrode placement in a private area. Upon contrac-tion each muscle was palpated, the skin cleansed withalcohol wipes, and hair trimmed in the area to assurefirm electrode adherence. The EMG electrodes wereplaced on the muscle belly, parallel to the line of ac-tion on the following muscles: quadriceps (left), bi-ceps femoris (right), hip adductors (left), hip abduc-tors (right), gluteus maximus (left), and gastrocnemius(right) based on the instructions by Florimond [14]and Gullet et al. [6]. Reference images of the elec-trode placement can be found online in the Flori-mond [14] manuscript on pages 18–19 (http://www.thoughttechnology.com/pdf/manuals/MAR908-03%20SEMG%20applied%20to%20physical%20rehabilitation%20and%20biomechanics.pdf). Surface electrodeswere chosen, hence the system was non-invasive andpainless [15].

The athletes performed a dynamic warm-up fol-lowed by several squats (at approximately 50% ofhis/her maximum) to simulate the testing protocol. Theathletes were randomly assigned to the order of datacollection (hip belt squat no band, hip belt squat withband, back squat) with all data collected in one sessionfor consistency of the EMG electrode placement. Thesequence for each device was as follows:

1. A pre-determined 8-RM weight load (Table 1)was racked for each athlete with the safety pinsecurely placed;

2. The bench was positioned behind the athlete suchthat the squat will be achieved to a level at whichthe knees are at 90 degrees of flexion and thethighs are parallel to the floor;

Fig. 2. Hip belt squat and surface electrode set-up.

3. The athlete donned the belt or positioned the bar-bell behind the shoulders in a position he/she pre-ferred (either low bar or high bar);

4. The athlete placed his/her feet shoulder widthapart (on either side of the cylinder for the hipbelt squat) to standardize positioning [16,17] andplaced arms in front of the chest (goblet position)for the hip belt squats (Fig. 2);

5. The athlete was instructed to perform the squatsin a slow and controlled manner;

6. The athlete was reminded to lower his/her bodyto the point of their buttock touching the bench,to keep his/her back vertical, & to keep knees outto the side (these are all standard squat instruc-tions);

7. The athlete performed 4 repetitions of each squattechnique with EMG data collected on repetition#2, 3, and 4;

8. The athlete was given five minutes of rest be-tween each device to allow for adequate musclerecovery.

3. Results

The age, stature and weight were 26.3 ± 8.9 years,1.76 ± 0.07 meters, 90.1 ± 11.7 kg (men) and25.3 ± 13.2 years, 1.62 ± 0 meters, 56.7 ± 1.9 kg(women). Root Mean Square (RMS) is the techniqueused for rectifying the raw signal to convert it to anamplitude envelope and make it easier to view. The

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Table 2Mean ± standard deviation of EMG activity by gender and muscle of each squat technique

Belt squat no band Belt squat with band Back squatQuadriceps Female 724 ± 220 690 ± 284 646 ± 146

Male 774 ± 218 789 ± 220 697 ± 199

Biceps Femoris Female 106 ± 13 148 ± 26 148 ± 36Male 140 ± 40 156 ± 56 186 ± 129

Gluteus Maximus Female 296 ± 388 290 ± 343 271 ± 295Male 227 ± 118 247 ± 130 328 ± 185

Hip Abductors Female 274 ± 68 306 ± 80 288 ± 55Male 396 ± 219 397 ± 236 394 ± 179

Hip Adductors Female 285 ± 104 206 ± 33 238 ± 56Male 178 ± 57 179 ± 65 242 ± 93

Gastrocnemius Female 90 ± 13 90 ± 20 94 ± 3Male 131 ± 72 133 ± 54 156 ± 102

∗Display is in µV; Note: Root Mean Square (RMS) is the technique used for rectifying the raw signal to convert it to an amplitude envelope andmake it easier to view.

Table 3Ratio of reciprocal muscle groups involved in each squat technique by gender

Ratio Belt squat no band Belt squat with band Back squatQuadriceps : Biceps Femoris Female 6.81 : 1 4.67 : 1 4.38 : 1

Male 5.52 : 1 5.05 : 1 3.74 : 1

Abductor : Adductor Female 0.96 : 1 1.48 : 1 1.21 : 1Male 2.22 : 1 2.22 : 1 1.63 : 1

Adductor : Biceps Femoris Female 2.69 : 1 1.39 : 1 1.61 : 1Male 1.27 : 1 1.16 : 1 1.30 : 1

∗Ratio is in µV on EMG activity.

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Fig. 3. Mean EMG activity of the quadriceps muscles by device.(Colours are visible in the online version of the article; http://dx.doi.org/10.3233/IES-150570)

mean ± standard deviation of EMG muscle for eachsquat technique is displayed in Table 2. Muscle ra-tios of three commonly complimentary muscle groups(quadriceps: biceps femoris, abductor:adductor, andadductor:biceps femoris) are displayed in Table 3.ANOVA revealed no significant difference in muscleactivity between devices. The only muscle group sta-tistically different between genders was the gastrocne-

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Fig. 4. Mean EMG activity of the biceps femoris muscles by device.(Colours are visible in the online version of the article; http://dx.doi.org/10.3233/IES-150570)

mius (p = 0.04). A graph for each muscle group bydevice is displayed in Figs 3–8.

4. Discussion

The quest to find new methods to improve strengthand athletic performance is perpetual. The squat ex-

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Fig. 5. Mean EMG activity of the gluteus maximus muscle by device.(Colours are visible in the online version of the article; http://dx.doi.org/10.3233/IES-150570)

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Fig. 6. Mean EMG activity of the hip adductor muscles by device.(Colours are visible in the online version of the article; http://dx.doi.org/10.3233/IES-150570)

ercise is frequently employed by both healthy andrehabilitating athletes. This closed-kinetic chain taskis popular for reducing tibial-femoral shear forces inanterior cruciate ligament (ACL) rehabilitation [17],patello-femoral tracking dysfunctions (PFTD), and to-tal knee replacement therapy [5]. However, individu-als with various co-morbidities of the shoulder or spinemay experience limitations in performing a traditionalback squat. People with a history of shoulder impinge-ment, labral injuries, or thoracic outlet may not be ableto position the bar correctly behind the shoulders [10].People with a history of lumbosacral dysfunction mayalso have difficulty challenging the lower extremitieswith a load that does not surpass the tolerance of thespine [10].

The current study sought to explore the muscle re-cruitment patterns of a hip belt squat (with and with-out elastic bands) versus the barbell back squat. Un-like other marketed hip belt devices which use a fixedleverage arm or cable, the Squatmax-MD hip belt usesa free-weight-on-guide-rod design to keep the weight

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Fig. 7. Mean EMG activity of the hip abductor muscles by device.(Colours are visible in the online version of the article; http://dx.doi.org/10.3233/IES-150570)

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Fig. 8. Mean EMG activity of the gastrocnemius muscle by device.(Colours are visible in the online version of the article; http://dx.doi.org/10.3233/IES-150570)

centered directly under the lifter and reduce excessivestrain to the lumbar spine. The device was designedto be used with resistance bands to modify the kinet-ics and improve the training effects of the squat move-ment [13]. Under usual conditions, the length-tensionrelationship of muscle activity follows a “bell-shaped”strength curve with maximal force production in themid-range of the motion [12]. When using an elasticband with a squat, the band elongates as the bar ismoved upward. This elongation adds resistance to themotion. The resistance increases in a curvilinear pat-tern as the band elongates and reaches the peak resis-tance at the most vertical position of the squat. This isthe point where an individual is normally deceleratingwhen not using an elastic band. However, when using aband with the squat, the lifter must continue to recruitmotor units until full “lockout” is complete [13,18].Likewise, with full band elongation and increased re-sistance, the descending motion of the squat requiresan increase in control of the eccentric action.

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Wallace et al. [19] examined the influence of elas-tic bands on the back squat. They tested 10 resistance-trained individuals at 60% and 85% 1-RM with andwithout the use of elastic bands. The results revealedthat peak force and peak power were greater using elas-tic bands for a back squat. Stevenson et al. [20] stud-ied 20 individuals performing free-weight back squatswith and without elastic bands. The added band forcerepresented 20% of the 55% 1-RM. Peak eccentricforces and rate of force development were greater withthe bands. Whereas, peak concentric forces and meanconcentric velocity were greater without the bands.

Foot placement for the squat technique is a con-sideration when comparing muscle activity. Paoli etal. [17] studied the activity of eight muscle groups withthree different loads and three different stance posi-tions (100%, 150%, 200% of greater trochanter dis-tance). Only the widest stance width increased gluteusmaximus activity. In a study by Escamilla et al. [21]muscle activity of leg press and squat techniques werecompared for wide vs. narrow and high vs. low footplacements. The vasti medialis and vasti lateralis mus-cle activity was the same with both narrow and widefoot placement on the foot plate of a leg press machine.Likewise, vasti muscle activity was the same for bothlow and high foot placements with the leg press. Ham-string activity was greater with a wide vs. a narrow footplacement but gastrocnemius activity was greater witha narrow vs. wide foot placement. For the squat tech-nique the vasti and hamstring activity was the samefor the wide and narrow foot placements. Given thatstance width for all conditions in the current study wereat shoulder width, each individual served as their owncontrol and it was not expected to influence the com-parisons of muscle activation.

When comparing the three techniques in the cur-rent study, muscle activity of the quadriceps was higherwith both hip belt squats than the back squat (for bothgenders). Whereas, hamstring activity was higher inthe back squat than the belt squat techniques. Withthe use of the resistance band in the belt squat, ham-string activity increased for both genders. Among fe-males, the hamstring activity during the hip belt squatwith band was similar to that of the back squat. Thisis important in both athletic training and rehabilitationsince engaging quadriceps disproportionately to ham-strings (Table 3) may reduce joint stability and increaseanterior tibial translation with strong quadriceps ac-tion [4,22]. However, the squat exercise is not knownfor high hamstring activity [23]. Prior studies reportedthat the squat only yielded 27% of maximal voluntaryisometric hamstring activity [3,24].

Gullett et al. compared the front squat to the backsquat [6]. They reported that the back squat compres-sive forces on the knee were higher (11.0 ± 2.3 N)than the front squat (9.3 ± 1.5 N). With the techniqueused for the hip belt squat being closer to that of a frontsquat, one would expect the knee compressive forcesto be reduced when compared to that of a back squat.

When examining muscles of the medial and lateralthigh, hip adductor activity was lowest and hip abduc-tor activity was highest when performing a hip beltsquat with the band for both genders. Likewise, Table3 reveals the best hip adductor to biceps femoris ratiowas using the hip belt squat with the band. This maybe an important factor when dealing with individualswho have excessive knee valgus, a tendency for ACLinjury, or when recovering from ACL surgery. The ab-ductor to adductor ratio is higher with the hip beltsquat technique. This implies the hip abductors willincrease in strength more than the hip adductors. Nu-merous research studies have demonstrated the impor-tance of hip abduction and external rotation strengthin improving landing technique, preventing ACL andPFTD [4,25–30]. Baldon et al. [31] also identifiedthe importance of eccentric hip abduction strength inclients with PFTD. This is a significant plus for the useof the hip belt squat.

5. Conclusions

In summary, given the lack of significant differencein the muscle activity when comparing the barbell backsquat to the hip belt squat, one needs to look at otheradvantages or disadvantages to determine the clinicalvalue. One positive attribute for the hip belt squat is theability to unload the shoulders and spine. This couldallow many people who find the barbell back squatexercise too difficult another avenue for weight bear-ing lower extremity strengthening. Another positive at-tribute for the hip belt squat is the hip abductor to ad-ductor ratio, which could be very important for futureinjury prevention. While the back squat has slightlyhigher hamstring recruitment, which is important inACL injury prevention, the hip belt squat may addressthis by offsetting the free weight with the use of an ad-ditional band. Thus, if a free weight hip belt squat de-vice is available, it may be a better alternative to the tra-ditional barbell squat technique. Further research maybe beneficial to determine if increasing band tensionwith the hip belt squat increases hamstring activationduring the exercise.

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Acknowledgements

Special thanks to DJO Global (Vista, CA) for theirgenerous loan of the Chattanooga surface EMG ma-chines for data collection and Brian Henesey for theuse of the belt squat machine at his facility Over-Achieve Sports and Speed LLC.

Conflict of interest

The authors declare there were no conflicts of inter-est of any kind in any aspect of this research study.

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