Re: A Biomechanical Comparison of Back and Front Squats

[Guest guest]

Hi

This is interesting, however I would like to see the actual squats

performed, for me I tend to experience more knee discomfort following

training blocks of front squating and not following block of back squats.

My knee issues may be described in another post, but I find this

characterisation interetsting. Also normaly the weight that I handle in

back squats is much higher than in front squats, doe this influence

compressive loading, and torque mentioned in the study?

Regards

Nick Tatalias

Johannesburg

South Africa

2008/12/14 carruthersjam

>

> A Biomechanical Comparison of Back and Front Squats in Healthy

> Trained Individuals.Gullett JC, Tillman MD, Gutierrez GM, Chow JW.

>

> J Strength Cond Res. 2008 Nov 8. [Epub ahead of print] Links

>

> The strength and stability of the knee plays an integral role in

> athletics and activities of daily living. A better understanding of

> knee joint biomechanics while performing variations of the squat

> would be useful in rehabilitation and exercise prescription. We

> quantified and compared tibiofemoral joint kinetics as well as muscle

> activity while executing front and back squats. Because of the

> inherent change in the position of the center of mass of the bar

> between the front and back squat lifts, we hypothesized that the back

> squat would result in increased loads on the knee joint and that the

> front squat would result in increased knee extensor and decreased

> back extensor muscle activity. A crossover study design was used. To

> assess the net force and torque placed on the knee and muscle

> activation levels, a combination of video and force data, as well as

> surface electromyographic data, were collected from 15 healthy

> trained individuals.

>

> The back squat resulted in significantly higher compressive forces

> and knee extensor moments than the front squat. Shear forces at the

> knee were small in magnitude, posteriorly directed, and did not vary

> between the squat variations. Although bar position did not influence

> muscle activity, muscle activation during the ascending phase was

> significantly greater than during the descending phase.

>

> The front squat was as effective as the back squat in terms of

> overall muscle recruitment, with significantly less compressive

> forces and extensor moments. The results suggest that front squats

> may be advantageous compared with back squats for individuals with

> knee problems such as meniscus tears, and for long-term joint health.

>

> ============================

> Carruthers

> Wakefield, UK

>

>

>

[Guest guest]

Thanks Nick! I was reading the study and thinking exactly this - and for some

reason front squats bug me, but obviously I'm moving a lot more weight on back

squats. I think there has to be something about the set up they used - if they

did narrow, foot forward squats for both, then fronts might be " easier " on the

body? However, if they let the athlete select a regular back squat - shoulder

width wide or better, with foot rotation if needed?

The Phantom

aka Schaefer, CMT, competing powerlifter

Denver, Colorado, USA

-------------- Original message --------------

Hi

This is interesting, however I would like to see the actual squats

performed, for me I tend to experience more knee discomfort following

training blocks of front squating and not following block of back squats.

My knee issues may be described in another post, but I find this

characterisation interetsting. Also normaly the weight that I handle in

back squats is much higher than in front squats, doe this influence

compressive loading, and torque mentioned in the study?

Regards

Nick Tatalias

Johannesburg

South Africa

2008/12/14 carruthersjam

>

> A Biomechanical Comparison of Back and Front Squats in Healthy

> Trained Individuals.Gullett JC, Tillman MD, Gutierrez GM, Chow JW.

>

> J Strength Cond Res. 2008 Nov 8. [Epub ahead of print] Links

>

> The strength and stability of the knee plays an integral role in

> athletics and activities of daily living. A better understanding of

> knee joint biomechanics while performing variations of the squat

> would be useful in rehabilitation and exercise prescription. We

> quantified and compared tibiofemoral joint kinetics as well as muscle

> activity while executing front and back squats. Because of the

> inherent change in the position of the center of mass of the bar

> between the front and back squat lifts, we hypothesized that the back

> squat would result in increased loads on the knee joint and that the

> front squat would result in increased knee extensor and decreased

> back extensor muscle activity. A crossover study design was used. To

> assess the net force and torque placed on the knee and muscle

> activation levels, a combination of video and force data, as well as

> surface electromyographic data, were collected from 15 healthy

> trained individuals.

>

> The back squat resulted in significantly higher compressive forces

> and knee extensor moments than the front squat. Shear forces at the

> knee were small in magnitude, posteriorly directed, and did not vary

> between the squat variations. Although bar position did not influence

> muscle activity, muscle activation during the ascending phase was

> significantly greater than during the descending phase.

>

> The front squat was as effective as the back squat in terms of

> overall muscle recruitment, with significantly less compressive

> forces and extensor moments. The results suggest that front squats

> may be advantageous compared with back squats for individuals with

> knee problems such as meniscus tears, and for long-term joint health.

>

> ============================

> Carruthers

> Wakefield, UK

>

>

>

[Guest guest]

Hi Jerry

In responset to this

-----Because the muscles tested were equally active during the front squat

while lifting less mass, it is presumable that the same workout

can be achieved with less compressive forces on the knee.

Telle -- That or the results are inaccurate artifacts of the measuring

devices. When I had my EMG system I got some really strange results --

indicating something I never could explain. On one occasion I tested

the SEMG of the 1 arm dbbl row using 60 and 90 lbs. There was no

apparent difference!! Was it the location of the sensors -- the high

and low pass filters -- more rhomboid activation?? Aside from my

ignorance I'm not so sure we can rely on the above either? for

instance do they give exact data of the samples as in ROM sampling or

are they rep means.

************************

It occured to me that if muscle activation is measured by amplitude of the

wave on the EMG, how big an area is measured, is the measure not limited

in the number of units that it can read? My logic tells me that if you lift

more load you recruit more muscle fibres, does the EMG recived the extra

number of fibres being recruited, lets say the amplitude of each recruitment

is the same (the maximum recruitment for each motor unit as the load is

heavy enough to require the maximum out of a motor unit), but the number of

these units being recruited may change yet the amplitude still reads the

same and thus a conclusion that activation is the same, when it is not.

Regards

Nick Tatalias

Johannesburg

South Africa