Calf Exercise Analyses

Plantar Flexors

Plantar Flexion exercises can be viewed either as a 1st class lever or a 2nd class lever system depending on the perspective of what constitutes the axis :

Calf Press can be seen as a 1st class lever system

  • Motive Force: Weight on Leg Press Sled transferred to the ball of the foot
  • Axis: Ankle joint
  • Resistive Force: Plantar Flexors attached at Calcaneus

Calf Raises, although essentially similar to the Calf Press, could be classified as a 2nd class lever:

  • Axis: Ball of Foot
  • Motive Force: Bodyweight plus added weight transferred through ankle
  • Resistive Force: Plantar Flexors attached at Calcaneous

See all Plantar Flexion exercises.

Tension Curve

Smith Standing Calf Raise

Unlike most other exercises, the calf raise (typically performed on an elevated calf block) or calf press movements (performed off the lower edge of a leg press) experience a relative continuous tension curve throughout the entire range of motion. Unless the heel rests momentarily on the floor or exercise apparatus, the plantar flexors (namely the Gastrocnemius and Soleus) must maintain tension. In this lower stretched position the Stretch-Shortening Cycle allows the muscles to overcome an otherwise decreased tension potential of stretched muscles.

Also, the upper portion of the calf exercises is relatively more difficult compared to the finishing resistance of other exercises. This is because, in most people, the ankle cannot extend straight like other joints. Also, see Ankle/Subtalar ROM. This 'incomplete lockout' leaves a significant horizontal distance between the resistance (load transferred through ankles and fulcrum (ball of the foot under forefoot) at full plantar flexion.

Positioning the load slightly back relative to the feet increases the required tension nearer the top of the motion by increasing the horizontal lever arm distance. As a result greater tension is required to obtain and hold this upper extended position.

Conversely placing the load, slightly forward relative the feet allow for something closer to a lockout where the ankle is more above the ball of the foot. This permits a subtle decrease of muscle tension nearer the top of the resistance curve, resulting in a slightly more dynamic resistance curve.

Knee Position

Calf exercises like the Standing Calf Raise or Calf Press, both with the knees straight, activate both the Gastrocnemius and Soleus. However in the case of the Seated Calf Raise, with the knee bent, the Soleus becomes the primary plantar flexor since the Gastrocnemius remains in Active Insufficiency. For the biarticulate gastrocnemius to plantarflex through the ankle, it must be at least partially stretched across a straight or nearly straight knee.

Although calf raises are most commonly performed with the knees straight throughout the movement, some individuals choose to bend their knees slightly at the bottom of the standing calf raise and extend their knee as they raise the weight upward. In theory, this may make at least some sense being that a biarticulate muscle such as the gastrocnemius loses its ability to produce force when it is stretched across both joints simultaneously. See Muscle Length-tension Relationship. However the Stretch-shortening Cycle at least partially offers compensation for this lost force production assuming the concentric contraction immediately follows the stretch or end of the eccentric phase. Interestingly, this movement pattern with a small knee bend at the bottom-most position is a bit similar to a jumping motion where the knees initially bend then straighten at the top of the jump. The standing calf raise performed with a small bend at the bottom is performed with far less speed and involvement from the quads and glutes.

Hip Position

Lever Donkey Calf Raise

Exercises such as the Seated Calf Press, 45° Calf Press, Seated Calf Extension, and Donkey Calf Raise offer slightly different muscle dynamics as compared to the Standing Calf Raise or the Lying Calf Press.

Significant flexion of the hip with knee straight stretch the biarticulate hamstrings cross both hip and knee. Hamstrings pull against Gastrocnemius since they slightly wrap around each other from behind the knee. This places the point at which the stretch occurs in the calf slightly higher in the movement, decreasing the range of motion at the bottom. Therefore, the Stretch-shortening Cycle occurs in a slightly less shallow position as compared to calf exercise with the hips extended.

However, the flexed hip position permits greater tension potential of the gastrocnemius muscles near the top of the movement, or the end portion of ankle plantar flexion, a position where tension potential would normally dissipate sooner, if not for the pull on the gastrocnemius by the stretched hamstrings. It appears, for this reason, slightly greater resistance can be used on the seated calf press with back support slightly more upright, as opposed to reclining back further.

However, for those with less hamstring flexibility, the seat can be positioned too upright resulting in either a subtle flexion through the lumbar spine or a slight knee bend (possibly asymmetrically on the tighter hamstring side), particularly during dorsal flexion of the ankle, again due to the Hamstrings / Gastrocnemius interaction and Passive Insufficiency.

Although the involvement of the lateral and medial heads of the Gastrocnemius would not seem to be altered by medial or lateral rotation of the hip, magnetic resonance imaging (MRI) research by Dr. Per Tesch (Sweden) suggests "toes in" activate both heads and "toes out" activate the medial head to a higher degree.

Involvement In Other Exercises

The Gastrocnemius can assist in knee flexion (ie: Leg Curl) when the ankles are dorsal flexed. The plantar flexors also assist during the Squat and other compound Quadriceps exercises where the knee moves forward from the ankle. In these leg movements, the Gastrocnemius acts as a Dynamic Stabilizer (moving across the ankle and knee joints simultaneously) and the Soleus as a Synergist by dorsal flexing the ankle. The plantar flexors are also involved in exercises involving jumping such as lower body plyometrics and Olympic Weightlifting.

Dorsal Flexors

The muscle that dorsal flex the ankle include Tibialis anterior, Extension digitorum longus, Extensor hallucis longus, and Peroneus Tertius. The Tibialis Anterior is the most predominant superficial muscle situated on the anterior portion of the lower leg, slightly lateral and superior. These muscles can be exercised by reverse Tibia Raise, Calf Raises, and Reverse Calf Press. See all Dorsal Flexor exercise variations.

Most exercises targeting the Tibialis anterior and other dorsal flexors have varying versions of a largely continuous tension curve with an opportunity to relax or decrease activation at the lower starting position.

Tibia Raise

In the Tibia Raise, the added resistance rests on the top of the foot and is pulled upward. This exercise forms a third class lever system:

  • Axis: Ankle
  • Resistive Force: Dorsal Flexors
  • Motive Force: Added Weight

Although the dorsal flexors have the opportunity to relax a the bottom of the lift, torque is relatively high throughout movement since the range of motion of the ankle does not allow the horizontal distance of the resistance to reach proximity to the ankle.

Reverse Calf Press

Sled Lying Leg Curl

The Reverse Calf Press involves placing the feet high on a leg press platform and pushing off with the heels by pulling the feet toward the shins. Depending on what might be considered the axis (Heel or Ankle), the Reverse Calf Press can be seen as a first-class lever system:

  • Motive Force: Weight on Leg Press Sled transferred to the heel of the shoe
  • Axis: Ankle
  • Resistive Force: Dorsal Flexors

Typically the feet will place flat on large foot platform of the leg press in the highest possible position allowing for a full range of motion yet not so high to exceed hip flexibility or risk slippage. Many leg press platforms are tall enough so the entire length of the bottom of the feet will make contact with the platform in the starting bottom position. This may allow for a momentarily rest at the bottom position between each rep.

Exercising the muscles and joints through a full range of motion is sacrificed if the feet are positioned too low on the platform, not allowing for full plantar flexion at the initiation of the movement. This is also the case where the ankles are so flexible that the highest available position still does not permit complete plantar flexion in the starting position.

If the foot is placed slightly higher than the maximum height that allows for complete plantar flexion, the sole of the shoe will be angled slightly off of the surface, with contact only on the heel of the shoe. In which case the resistance momentarily rests through the ankle joints, with only the shoe heel secured to the platform surface via compression and friction. At the bottom of the motion, this slightly higher position may more likely activate a Stretch-shortening Cycle in the muscles that dorsal flex the ankle.

In any starting position, the resistance will begin relatively high once the foot begins to dorsal flex. The relative distance from the heel and the ankle perpendicular to the line of force determines the relative torque force throughout the movement.

In contrast to the seated calf press, discussed above,  on the seated reverse calf press, less resistance can be used when the seat is more upright, due to the resistance created by the intersecting lines of pull between the hamstring and gastrocnemius. Positioning the seat in a more reclined or supine position is recommended, permitting a fuller range of motion. This interaction between the hamstrings and gastrocnemius also occurs during the sit and reach test with the feet positioned vertically on the side of a sit and reach the box.

Reverse Calf Raise

In the Reverse Calf Raise, the body gets lifted, typically along with an added weight. If the heel is seen as the axis, the Reverse Calf Press would constitute a second class lever system:

  • Axis: Corner of calf block to the heel of the shoe
  • Motive Force: Bodyweight plus added weight transferred through ankle
  • Resistive Force: Dorsal Flexors

In contrast to the Reverse Calf Press, the Reverse Calf Raise generally begins with the mid to rear portion of the soles secured to the front of calf block through compression and friction, with a few exceptions depending on the apparatus. The initial torque force can be reduced by placing the feet further back so the front corner of the calf block rest closer under the ankle, or even more so, by positioning ankles slightly behind the front corner of the calf block. In an initial position (more forward or more back), the feet will initially rotate off the corner of the block. As soon as the soles are raised beyond horizontal (or more accurately, beyond parallel to the upper surface of the calf block), torque increases significantly since the soles now rotate off the back of the heal instead of the more anteriorly above the front of the calf block. However, those lacking ankle flexibility or dorsal flexion strength may not be able to raise their feet higher than horizontal to the calf block surface.

Hip Position Analysis

Dorsal Flexion exercises performed with a significantly flexed hip, such as Lever 45° Reverse Calf Press and Lever Donkey Reverse Calf Raise can either decrease the upper range of motion or at least make the topmost portion more difficult due to a series of interactions between muscles affecting a joint range of motions. Positioning the hip in a flexed position with the knee straight pulls the biarticulate hamstrings cross both the hip and knee. The taut Hamstrings pull the upper portion of both heads of the Gastrocnemius inward due to their partially overlapping position behind the knee. This overlap pulls on both the hamstrings and gastrocnemius when they are simultaneously stretched across the knee and their adjacent biarticulate joints, hip, and ankle respectively. The pull of hamstrings on the gastrocnemius in this position decreases the ankles range of motion making it more difficult or impossible to achieve complete dorsal flexion. Those with poor hamstring flexibility may have a slightly arched (flexed) spine when the hips are flexed sharply, particularly during ankle dorsiflexion. Also, see Passive Insufficiency.

Involvement in Other Exercises

Dorsal Flexors can be used during the last portion of the push-off phase in the lunge where the heal leaves the floor with an additional heal push from ankle dorsiflexion. During the landing phase of the lunge, the dorsal flexors also contract eccentrically when the heel makes initial contact with the floor, acting to cushion the landing onto the entire sole.

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