How to Perform the Donkey Calf Raise
Many people have a love or hate relationship with their calves. Thanks to genetics some of us can develop large calves with little to no direct stimulus while others can't seem to grow their calves no matter how many reps and sets they perform. Although there are a number of exercises directly targeting the calves, they remain a stubborn muscle group for many athletes.
The calves are comprised of two main muscles ? the gastrocnemius and soleus. These muscles are worked ankle plantar flexion, a movement in which the ankle is extended and toes are moving away from the shins.
The donkey calf raise is an isolation push exercise targeting the gastrocnemius, which is comprised of the medial and lateral heads. The soleus acts as a supporting muscle group during this movement.  Supporting muscle groups assist the target muscle group in completing the movement. The serratus interior (boxer?s muscle), pectoralis minor, and both heads of the pectoralis major (sternal and clavicular). 
Stabilizer muscles help maintain a posture or fixate a joint by contracting without significantly moving.  the donkey calf raise is an excellent calf isolation exercise that doesn't put a lot of stress on the lower back.
MTS Nutrition CEO Marc Lobliner provides an explanation of proper donkey calf raise form.
How to Perform the Donkey Calf RaiseYou can perform donkey calf raises using a variety of setups ? a lever-loaded machine, plate-loaded machine, weighted sled, smith machine, a dip belt, or with a partner sitting on your back. Specialized machines for perform the donkey calf raise can be hard to find.
The most common setup alternatives involve hanging weight from a dip belt and leaning up against an object or allowing a partner to sit on your back with a platform under your toes. Although this walkthrough will focus on performing donkey calf raises with a machine, the general form and tips can be applied to all setup variations.
Approach the donkey calf raise machine and select the appropriate working weight. If this is your first time performing the exercise then pick a conservative weight that you can safely lift for 8 to 12 repetitions. This working weight will likely be less than the amount you use for standing calf raises.
Bend your knees and position your body under the lower back pad. Your toes and mid-foot should be in contact with the foot platform. Places your forearms on the supporting pad and grip the handles; it's OK if your elbows hand slightly off the pad.
Extend your knees and straighten your legs so that the upper hips and lower back are in-contact with the padded support. At this point you should feel tension on your calves but the weight stack shouldn?t have moved.
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This is your starting position. If you find yourself needing to excessive bend the knees to get in to position then adjust the lower pad up. If your hips aren?t in contact with the pad then move it downwards.
Take a breath, brace your abdominals, squeeze the glutes and begin raising your heels and pushing your toes away from your shins. Continue pushing and raising your heels and ankles as high as possible. At the top of this position you should feel a deep contraction in the calf musculature on the back of your lower leg.
Once you've held the top of the movement for the desired duration lower the lower back pad in a slow and controlled motion back to the starting position. Your legs and knees should remain straight, but not hyperextended throughout the entirety of this movement. The movement pattern for the lowering portion should be the exact reverse of the pushing portion.
Complete for the desired number of repetitions. Some trainees find that slightly bending the knees during the lowering and stretching portion of the lifting feels more natural. If you choose to employ this technique then ensure your legs and knees are straight during the pushing portion.
During the donkey calf raise your hips should be higher than your upper back and shoulders for a large majority of the exercise. As seen in Marc?s demonstration your back should be neutral or slightly rounded in a C-shape to ensure you?re engaging and pushing with your calves rather than your lower back.
Some lifters choose to exhale while pushing the lower back support upwards, at the top of each rep, or in between in each repetition. Choose a breathing pattern that feels the most natural and comfortable for you.
This exercise can be performed using straight sets, pre-exhaust sets, drop sets, rest-pause sets, supersets, trisets, giant sets, paused reps, partial reps, forced reps, or slow negatives. As with any exercise, the two most important components are high-quality form and progression. Progression can take a variety of forms (e.g. more weight, sets, or reps, decreased rest period, improved rep quality, etc?) but strive to improve every training session.
Donkey Calf Raise Form TipsHold the Squeeze ? Increase intensity by holding the top position, with the ankle fully flexed, for 5 to 10 seconds. Focus on squeezing the calves as hard as possible.
This hold will increase time under tension and the burn in the gastrocnemius and soleus. Increased time under tension is an excellent variable to adjust for progressive overload and enhanced muscle growth.
Hold the Stretch ? Increase intensity and remove the stretch-reflex by holding the bottom position for 3 to 5 seconds. Focus on lengthening your calf as much as possible and pulling your toes towards your shins.
This hold will increase time under tension and minimize the bounce commonly used by trainees who want to rush through their calf workout. If you?re a true masochist then experiment with holding the top and bottom position of each rep for 3 to 5 seconds. Prepare yourself for some serious Delayed Onset Muscle Soreness (DOMS) afterwards.
Feel the Burn ? While the most commonly recommended rep range to induced muscle hypertrophy is 8 to 12 reps, some athletes prefer to use and respond better to significantly higher rep ranges when training their calves. Sets of 15 to 20 reps may be just what you need to get this stubborn muscle group to grow.
An increased number of reps per set increases time under tension and stress on the target muscle group; two key factors needed for muscle size gains.
Avoid Momentum ? Perform the donkey calf raise in a controlled full-range of motion. Check your ego at the door and don't immediately attempt to beat your standing calf raise personal records. Stay tight throughout the movement (abdominals and glutes squeezed) and don't allow your shoulder to roll-in or move up towards your ears.
Do not use momentum to swing the hips from the bottom to the top position. This momentum dramatically increases the likelihood of injury and minimizes the stimulus of the target muscles.
References1) Griffing, James, et al. "Lever Donkey Calf Raise." ExRx.net. N.p., 2015.
2) Griffing, James, et al. "Kinesiology Glossary." ExRx.net. N.p., 2015.