Fast bowling is reflexive
There are two reflexes that exist when it comes to bowling, which are the stumble and crossed-extensor reflexes. The stumble reflex is responsible for the horizontal movement of the lead leg between back foot contact and front foot contact (FFC) and the crossed-extensor reflex is responsible for vertical force production on back foot contact. It dictates the effectiveness and ultimately the stability and control on the key determinant of the delivery. The back foot contact [BFC]
Contralateral leg will always be at the same height as the ipsilateral leg.
What many don't understand is that outside of skill stability and static base work, bowling is a unilateral activity, meaning each leg doesn't do the exact same thing unless the contact allows it . Compliance on ground contact will inhibit the reflexive system. This is why I place a premium on isometric work, overloaded bowling and stiffness jumps. However, the action, effectiveness and coordination of the contralateral and ipsilateral leg has huge implications on the quality of the technical framework. Bowling is much more closely related to sprinting gait than many people think.
The reflexive action of the leading leg or the stable plant of the back foot on contact are both dependent on a powerful reflex system. This is yet another reason why relying on weights and barbell training to improve bowling speed will fall short if the reflexive systems of an athletes aren't powerfully active. Both reflexes are cutaneous receptors and are a type of sensory receptor, which respond to stimuli (touch, pressure, pain, temperature) that provide information regarding contact with the external environment. How bowlers interact with the environment dictates the response of both reflexes.
Key point to remember as reflexes when the skill is performed internally focusing and attempting to control them is pointless. However, training can consciously occur separately to help utilise their benefits. Reflexes can assist your bowling speed by applying more force into the ground.
If you want to change technique and utilise the reflexive system you need to learn to train the fascia system.
Reflexive elasticity is a property of the quality and composition of the fascia and tendons structures within the body. Fascia is composed of both collagen and elastin. Athletes who have a higher proportion of elastin, the portion of the fascia that can stretch and spring back easily, are generally better able to make use of elastic energy than their counterparts who might be too high in collagen proportion. This property of human movement can help to explain those athletes who are skinny and seemingly weak in the weight room yet are capable of extremely powerful and elastic movement in dynamic sport with their bodyweight.
Key message being, learn to sprint. The skill itself is the best training method you can do to utilise the reflexive system.