Howdy,
When it comes to running, there is many or slightly different technique you can see with runners (it depends of constitution, general motoric and learning experience, mobility and stability of proper joints…). In general, motor control plays the biggest role! This is a huge topic, therefore I will try to focus just on proper foot striking in any running type. In my opinion, there is a 3 ways you can strike ground with feet:
- “On toes” predominantly;
- Heel-midfoot-toes in a row;
- On toes-midfoot (forefoot).
When you attack ground with “toes” dominantly you utilize m. triceps surae tendon (Achilles tendon) elasticity on best way (and plantar fascia for sure). That’s good because you are losing minimum of your muscles energy which results less muscle and general fatigue (if you are a long distance guy for example). But whole leg system fatigue (less muscles included, constant legs-muscles stiffness, increased stabilizers work…) could be a problem among some people when “on toes” run, regardless that amortization in this type of running is the best – that’s mean less suffer on loaded joints (hip, knee and ankle). If some long distance runner (or whatever athlete) feels fatigue in calves for example, he(she) can “relax” with heel-middle-toes running for a while.
Running “on toes” is maybe not best option because m. quadriceps femoris is overloaded compared with other included muscles. I wanted to say that very important posterior chain muscles (m. gluteus maximus, hamstrings…) are less included when heel is off ground – which means that you lose stability and better strength (more muscles included – easier movement). This type of running maybe increase efficiency because of elasticity mentioned above, but it’s not the best option even in higher velocities because there is not enough stability (small support surface = small stability = instability). If you have less stability, prime movers can’t utilize their potential (strength) on the best way (unique rule in any movement)… Anything in this paragraph is not important too much in sprinting (because tendon elasticity is almost everything important there, and ground contact phase is the shortest) but it is in some other velocities (especially with lower velocities).
“On toes” predominantly running can be really good only when it comes to acceleration because of good elasticity (3rd option is good for deceleration but second not because the impact forces on joints are tremendous).

“On toes” running
In other way, heel-midfoot-toes running style is better when it comes to stability (best support surface), included muscles (posterior chain) and fatigue rate (more muscles included – less local fatigue rate). But in this type of running the problem is impact forces produced with heel-toes striking (become even worse if you have high shoes heels) which is not comfortable for contact leg joints (especially knee and shins). If we take sprint side of walk-sprint continuum, can you imagine sprinter who runs on heels?! The result is totally joint disaster – impact and braking forces are higher because of higher speed and foreleg strike the ground a bit further away from the body center of gravity compared with other two running types! Also, elasticity has less power than on toes running. But heel-middle-toes running style is not so bad option at all (if it’s not fast run) if you got “catlike silent running” (with the exception of sprint). Individualization and good technique is everything!

Heel-midfoot-toes running Heel-midfoot-toes in a row striking (impact forces)
Maybe the best option for long and short term running both is on toes-midfoot (forefoot) running. The good proof is barefeet running. Let’s do one test, take your shoes off and start to run naturally. Your feet will never allow “heel strike first” running when you are barefeet because subconsciously they are aware of high impact forces on joints in that case! They (actually your brain 🙂 ) naturally utilize the best option – the midfoot option (3rd option). Elasticity is highly utilized, stability is on high level, better posterior chain muscles utilizing (better than “on toes” running because of even slightly touching heels with ground.. you can note this even among sprinters where you need tendons elasticity utilizing as much as possible) which is important when it comes to better strength (it’s crucial in changing directions and deceleration).

On toes-midfoot (forefoot) running

On toes-midfoot (forefoot) striking
One more thing at the end. “The majority of people land on the outside (lateral) bottom of the foot and roll inward toward the big toe. This helps to distribute the force of your foot strike throughout your foot and leg and protect you from injury. The further you roll inward, the greater the protection against this force. However, when you roll in too much, your lower leg twists inward excessively, causing your kneecap to rub against the long femur bone behind it and cause pain. This is called Runner’s Knee.” – Gabe Mirkin
Thanks for reading and all the best,
Luka