Checklist: what to look for

Midsole

The midsole provides most of the cushioning. A layer of padding between the insole and the outsole provides shock-absorbing protection for the foot - it absorbs almost all of the impact when you're running or walking. It's made of shock absorbing foam, and may incorporate gel or air-sacks and plastic torsion supports.

The midsole is often the part of the shoe that wears out first. If you're tough on your shoes, ask for a pair with a midsole that will last. You can compare midsole softness among different shoes by squeezing the midsole with your thumb at both the heel and forefoot - the greater the indentation, the softer the midsole.

Remember, though, that a soft midsole will compress and grow flat faster than more rigid material.

• Cross-trainer Should be well cushioned with an even density throughout.
• Walking shoe Should have a relatively low midsole profile since a walker's cushioning needs are only moderate.
• Running shoe Should be firm, especially for heavy runners, and extra firm on the inside edge.

Eyelets

Extra eyelets at the top provide a snug fit for your ankle

Stitching

Stitching should be secure, even and straight, and not exposed in areas that get rough action. There shouldn't be any bulky seams or gummy adhesives.

Fusion welding involves bonding materials with heat and glue, rather than stitching. The idea is to increase durability without adding weight. It's worth looking out for.

Weight

Weight can vary significantly depending on brand and type of shoe. Be guided by a mix of common sense and your own preferences. If you're going to be pounding the pavement or go to the gym every day, don't get for anything too light or you probably won't get the support you need. If you're using cross-trainers just for casual walking around, they don't need to be heavy.

Tongue

Cushioned tongues help disperse shock, but the cushioning shouldn't be so big it makes the laces too hard to tie tightly.

Mid-foot shank

An insert found in the mid-part of the sole to stop excessive twisting. The stronger the shank, the more motion control it gives the shoe.

• Cross-trainer Look for an especially strong shank.
• Walking shoe Not so important.
• Running shoe Look for an especially strong shank.

Heel counter

A firm, usually plastic cup that grips the heel to keep from moving around in the shoe. A heel counter which doesn't hug the heel will affect stability and can lead to injury. All sports shoes need a firm heel counter.

Heel tab

The soft bit at the top of the heel counter. It should have a deep notch to allow your achilles heel to sit comfortably when you exercise.

Toe box

The tip of the shoe. It should be roomy enough for your toes to wiggle easily, and have a thumb's width gap between the end of your longest toe and the end of the shoe.

• Cross-trainer Your toes need enough space for side-to-side movement.
• Walking shoe Your toes need to be able to flex up and spread out during walking.
• Running shoe There should be enough flexibility in the toe area to allow sufficient push off.

Upper toe box

Synthetic mesh allows your shoe to breath

In-sole

The shoe layer nearest your foot. It provides extra shock absorption and arch support. The in-sole is removable and washable.

Outsole

The hard, patterned part of the sole that hits the ground. It may be blown rubber (soft) or carbon rubber (harder or more durable). Factors to consider include durability, flexibility, tread depth, grip, weight, breadth of the sole, breadth of the heel.

• Cross-trainer You want durability, grip and balance. Look for a solid rubber outsole that isn't too heavy. If you're using the shoes for court sports or aerobics, make sure they have very good grip.
• Walking shoe Look for a durable carbon rubber outsole. Blown rubber outsoles will reduce the weight, but wear out more quickly.
• Running shoe Look for a carbon rubber outsole or if you have a high arched foot, look for a softer, lighter outsole with a greater flexibility.

Flex grooves

Flex grooves are cut into the outsole to help the shoe bend and flex during exercise.

• Cross-trainer Flex grooves should be cut into the forefoot.
• Walking shoe Either the midsole material should be flexible or flex grooves should be cut into the sole.
• Running shoe Look for flex grooves which allow the shoe to bend during running.