Why We Keep Mentioning Cross-Trainers (and Why Running Shoes Can Mess With Your Form)

It's easily the most common thing we bring up with new members at Personal Space Fitness.

Wearing running shoes to a workout... No shade thrown here. We get it - they fall into the category of "fitness shoe". Most folks have a pair laying around somewhere. The simple fact is that they are designed for one thing: running. Before we get into why we push cross trainers so much (don't worry, we don't sell them), let's talk about why running shoes just don't work for fitness classes or strength workouts.

Running shoes are built for one direction

Running shoes do a great job… for running.

They’re designed for:

• forward motion

• repeated impact

• rolling you smoothly from heel to toe

  
  

That design comes with a few features that can be annoying in strength & conditioning workouts:

1) More heel cushion + a “slope”

Most running shoes have a thicker cushioned heel and a shape that subtly tips you forward. That’s helpful when you’re running. But when you’re trying to feel planted in a squat or stable in a lunge, that extra cushion and slope can make you feel like you’re getting nudged onto the front of your foot.

2) Slimmer toe box

Many running shoes narrow at the front. Again—fine for straight-ahead running.

But for lifting, bracing, and balance work, your toes want a little room to spread. A cramped toe box can change how your foot contacts the floor, which can change everything up the chain.

The “pushed into your toes” effect of running shoes

The gist: A thick, cushioned heel + a bit of slope + a narrow toe box can push you toward your toes.

When that happens, you’ll often see (or feel):

• heels popping up when you don’t want them to

• knees drifting forward more than they should

• wobbling on split squats/lunges

• foot cramping or “gripping” the floor

  
  

And the important part: your body is smart. If you’re off-balance, it will find a way to keep you upright.

Sometimes that correction shows up as a “huh… that doesn’t feel right” sensation during a movement. That’s often your body recruiting extra muscles just to stabilize you - muscles we aren’t even trying to train in that moment.

Over time, compensations like that can contribute to irritated feet/ankles/knees/hips or a “random” tweak feeling—especially when you’re tired. (You know the classic: “I threw out my back for no reason.” It’s rarely for no reason.)

What cross-trainers do differently (on purpose)

Cross-trainers aren’t less cushioned because brands forgot to make them comfortable. They’re built that way for a reason.

They’re designed for:

• multi-direction movement (not just forward)

• stability under load

• feeling the floor

  
  

That “feel the floor” part matters more than people expect. A firmer base gives you feedback: where your weight is, whether you’re balanced, whether you’re evenly planted through your whole foot. And when you can feel that, you can actually build balance instead of constantly correcting it.

Why this matters at Personal Space Fitness specifically

No workouts at PSF focus on “one thing.” We use scientific guidance when planning the schedule and workouts. They’re designed to balance:

• strength

• core control

• stability

• movement in directions people don’t practice much in daily life

  
  

Even on days that don’t look like agility training, you’re still stepping, bracing, rotating, carrying, shifting, and stabilizing. That’s part of why people feel better in real life after a few consistent weeks - because you’re getting stronger in positions and directions you don’t use much.

The Personal Space Fitness Training System

But the flip side is: shoes that only want to move forward (and that push you onto your toes) make that work harder than it needs to be. That’s why we recommend cross-trainers for our members. They’re simply built for how we train.

The easy, non-annoying takeaway

If you’re training with us regularly, cross-trainers are usually the better match.

If you’re not ready to get new shoes yet, no big deal - we just want you to be aware:

• If you feel pitched forward, unstable, or like your feet can’t settle… it might be your running shoes.

• If your coach keeps saying “get your whole foot down,” shoes may be part of the reason it feels hard.

  
  

All that said, if you're new to all of this, bring what you have. Ask a coach if you’re not sure. We’ve seen every shoe situation imaginable.

FAQ

Do I have to get cross-trainers to work out at PSF? No. You can start with what you have. This is just one of the most common “I don't feel comfortable” fixes.

What should I look for in a cross-trainer? A stable, firmer sole, enough toe box room to feel planted, and a shoe that feels secure when you move side-to-side.

Is it unsafe to lift in running shoes? Not right away. But many people feel less stable, get pushed into their toes, and compensate more - especially on single-leg or balance-heavy work.

Where are you located? Personal Space Fitness (Lindenwood Park) — 3401 Watson Rd, St. Louis, MO 63139.