The right amount of cushion in a running shoe depends on your body, your terrain, and how far you run. Most recreational runners land comfortably in the mid-range, with a midsole stack height around 28 to 35 mm at the heel. But cushioning isn’t a simple “more is better” equation. Extra foam changes how your body absorbs impact in ways that can help or hurt, and the type of foam matters as much as the amount.
How Cushioning Is Measured
Shoe cushioning is defined by stack height: the total thickness of material between your foot and the ground, measured in millimeters at the heel. Running shoes generally fall into three tiers. Low-cushion shoes sit around 27 mm or less at the heel. Mid-cushion shoes land in the 28 to 35 mm range. High-cushion (maximalist) shoes start around 35 mm and can reach 50 mm in some training models.
The other number worth knowing is the heel-to-toe drop, which is the difference in height between the heel and the forefoot. Most cushioned running shoes have a drop between 6 and 12 mm. A shoe with a 35 mm heel and a 28 mm forefoot has a 7 mm drop. Drop affects how your foot strikes the ground, while stack height determines how much material is absorbing each landing.
More Cushion Doesn’t Always Mean Less Impact
This is the counterintuitive finding that surprises most runners. A study published in the Orthopaedic Journal of Sports Medicine compared maximalist shoes to traditional neutral shoes before and after a 5K run. Runners in the maximalist shoes actually had a higher loading rate, meaning force hit their legs faster and harder per stride. Heel-strikers showed the biggest increase in impact forces when wearing the highly cushioned shoe.
The likely explanation is that thick, soft foam encourages runners to land harder, trusting the shoe to do the work. Your body naturally adjusts its stiffness and landing mechanics based on what it feels underfoot. When you sense a soft surface, you tend to strike with less caution. When you feel a firmer surface, your legs instinctively absorb more impact through muscle engagement and joint flexion. So piling on cushion can actually shift more stress to your bones and joints rather than your muscles, which are better equipped to handle it.
What the Foam Is Made of Matters
Two shoes with identical stack heights can feel completely different depending on their midsole material. Traditional EVA foam (the standard for decades) returns about 66% of the energy your foot puts into it. Thermoplastic polyurethane, a denser alternative, returns around 76%. The newest generation of foam, called PEBA, returns roughly 87% of that energy, meaning far less is lost as heat and compression with each stride.
PEBA is also significantly lighter and less dense than older foams, which is why modern maximalist shoes can have tall stack heights without feeling heavy. A shoe with 40 mm of PEBA foam weighs about the same as a shoe with 27 mm of EVA. This matters because shoe weight directly affects how much energy you spend per mile. The combination of PEBA foam and an embedded carbon-fiber plate is what powers today’s “super shoes,” which reduce the metabolic cost of running by about 4% on flat ground and roughly 3% on hilly courses. For elite marathoners, that 4% energy savings translates to about a 2.7% improvement in finishing time.
So the question isn’t just “how much cushion” but “what kind.” A moderately cushioned shoe with responsive, energy-returning foam can outperform a thick slab of dead, squishy material that absorbs your effort instead of giving it back.
How Your Body Affects the Choice
Heavier runners generate more force per stride, which is why the conventional advice is to choose shoes with more cushioning as body weight increases. There’s logic to this: extra mass means extra physical stress on bones and soft tissue with every footfall. But the relationship is more nuanced than a simple weight chart. Research has explored whether heavier runners actually do better in softer or stiffer shoes, and findings suggest that some heavier runners may benefit from firmer, more supportive midsoles rather than maximum softness, because firmer foam provides a more stable platform and prevents excessive compression.
Your foot strike pattern also plays a role. Heel-strikers tend to experience higher impact peaks and may benefit from moderate cushioning with a higher heel-to-toe drop that eases the transition from landing to push-off. Forefoot and midfoot strikers generate less sudden impact force because their muscles and tendons absorb the load more gradually, so they often prefer lower stack heights and less drop.
Road Versus Trail
Cushioning needs shift with terrain. Road running delivers repetitive, consistent impact on hard pavement, so road shoes prioritize softer midsole foam to buffer that pounding. Trail shoes take a different approach. Their midsoles are typically stiffer to create a stable platform on uneven ground, and many include a rock plate between the midsole and outsole that protects against sharp objects underfoot. That rock plate adds protection without requiring extra foam thickness.
If you run mostly on packed dirt or gravel paths, a moderately cushioned trail shoe works well. For technical, rocky terrain, stability and foot protection matter more than plush foam. For road running, you have a wider range of cushioning options because the surface is predictable.
Competition Rules Cap the Maximum
If you race, there’s an upper limit to be aware of. World Athletics regulations cap stack height at 40 mm for road racing shoes without spikes. For track events, the limit dropped to 20 mm as of November 2024. These rules were introduced specifically because super shoes with tall stack heights and carbon-fiber plates were producing such large performance advantages that regulators stepped in. For everyday training, there’s no cap, and some training shoes exceed 50 mm at the heel.
When Cushioning Wears Out
Even the best foam breaks down. Most daily training shoes maintain their cushioning properties for 300 to 500 miles. Lightweight racing shoes compress faster, lasting closer to 250 to 300 miles. Trail shoes also fall in the 300 to 500 mile range, though rough terrain can accelerate wear. You’ll feel the decline before you see it: the shoe starts to feel flat, your legs feel more fatigued after runs, or you notice new aches in your knees or shins. At that point, the midsole has lost enough resilience that it’s no longer doing its job, regardless of how the outsole tread looks.
Rotating between two pairs extends the life of both, because foam needs roughly 24 to 48 hours to fully decompress after a run.
Choosing the Right Amount for You
For most runners doing regular training on roads or sidewalks, a mid-cushion shoe in the 28 to 35 mm stack height range with responsive foam is the practical sweet spot. It provides enough material to soften repetitive impact without so much that it destabilizes your stride or encourages sloppy mechanics.
If you’re a larger runner (over 180 to 200 pounds) logging high weekly mileage, a stack height toward the upper end of that range can help manage cumulative stress, but look for foam that’s responsive rather than just soft. A shoe that compresses easily and doesn’t bounce back is adding weight without adding much protection.
If you’re transitioning between cushioning levels, do it gradually. Moving from a traditional shoe to a minimalist one requires your foot muscles to work significantly harder. Research shows that runners who transition to minimal shoes experience measurable increases in foot and lower leg muscle volume, meaning your feet are doing more work than they’re used to. Strengthening your intrinsic foot muscles before making the switch reduces injury risk. Going the other direction, from minimal to maximalist, is generally easier on the body but still worth easing into over a few weeks so your gait can adapt to the different ground feel.
The best test is paying attention to how your legs feel during and after runs. If you’re finishing runs with heavy, fatigued legs and sore joints, you may need more cushion or better foam. If your ankles feel unstable or your calves are unusually tight, you may have more shoe than you need.