w1 exercise analysis

8/3/2019 W1 Exercise Analysis

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Exercise analysis

Exercises for the legs


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Tips on exercise analysis

Analyses are of the concentric phase only

No need to analyse the two phases as the same musclesthat are active on the way up are also active on the waydown. Remember

The muscles that lift are the muscles that lower

These muscles shorten in the concentric phase & activelylengthen in the eccentric phase

Gravity lowers the load & lengthens the active muscles

Triceps activation not necessary in DB curls!!!


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Problems with two joint muscles

MRI evidence indicates that two joint musclessuch as rectus femoris & hamstrings are not

activated powerfully (if at all) during exercisesinvolving simultaneous hip and knee extension

Squats, leg press, lunge

During deadlift and power cleans thehamstrings

are more active because knee extensiondominates the first pull' of each movement andthen almost ceases during the second pull whenhip extension occurs almost in isolation


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Role of two joint muscles

Two joint muscles such as rectus femoris,hamstrings, sartorius, and gracilis are more heavilyactivated during single joint exercises than multi-

joint exercises because in the latter they most oftenhave undesirable actions at one joint

eg the hamstrings flex the knee and are therefore not

activated heavily during squats, leg press or lunge eg rectus femoris tends to flex the hip and is therefore

not activated heavily during squats, leg press or lunge


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When choosing an exercise

Is the target muscle group the limiting factor? eg. Are your quads the limiting factor when you squat?

If not, is another exercise, or a squat variant better? Does the exercise require the target muscle

to work through a large range of motion? If not is another exercise more appropriate?

Remember that greater stretch is associated with greatergrowth


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Technique variations

To target a specific muscle or muscle group

Increase stretch on the target muscle(s)

Decrease stretch on all other muscles Low feet/low seat leg press quadriceps emphasis

High feet/high seat glutes emphasis

Front squat quadriceps emphasis

Narrow grip bench press triceps emphasis

Use medium to narrow grip on lat-pulldowns

Do bicep curls on an incline bench

Do straight leg calf raises for gastroc. development


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Technique variations

To target a specific muscle or muscle group

Remember your functional anatomy and apply it

Supinate during DB curls to maximise b. brachiis role Use neutral grip curls to minimise b. brachiis role and

therefore emphasize brachialis

Use a neutral or supinated grip to train upper back

muscles The popular use of prone grips during chins is counter-

productive


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Conventional back squat


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Squat

Joint Action Major muscles involved

Knee Ext Quadriceps femoris

(Rectus femoris moderately active)

Hip Ext Gluteus maximus, mediusAdductor magnus

(Hamstrings hardly active)

Vert. Col. (Prevents Erector spinae, multifidis

flexion) Quadratus lumborum

Other significant stabilisers - adductors of the hip


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Magnetic resonance image

of the thigh after squats

Lighter shade:

heavy activity

Medium shade:

moderate activity

Darkest shade:

no activity

Images from Ploutz-Snyder et

al 1995 (insert) & Tesch, 1999


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Conventional squat

Barbell position

Barbell rests on trapezius

not higher on the neck


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Squat - width of stance

Conventional Wide


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Squat variations

Front squat

Compared to conventional squats this variation results in

a more upright stance & emphasises quads more and

glutes & back less


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Squat variations

Front squat

Many find it difficult to support the bar on the front of the shoulders.

Keeping the elbows high is vital. Typically only the extended fingers

rest on the bar, as few can manage a true grip!


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Squat variations

Low bar squat (powerlifting)

Compared to conventional squats this variation tilts the

trunk further forward & emphasises glutes & back more

and quads less


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Squat variations

Front squat Conventional Low bar

Circle size represents the torque required. Dashed line shows

CoM. The vertical distance from the joint to the CoM is the

length of each joints resistance arm

w1 exercise analysis

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