Breathing, Warm-Ups, and Form: Strength Training Safety Basics

Most beginner questions about strength training are about what to do. Just as important is how to do it: when to breathe, how to warm up, and which small habits keep joints comfortable. The National Institute on Aging (NIA), part of the National Institutes of Health, publishes a short set of safety tips for strength exercises, and the federal Physical Activity Guidelines for Americans explain where warm-ups, cool-downs, and stretching fit. Here is what both say.

1. Breathing: out on the effort, in as you relax

NIA's breathing advice is direct: don't hold your breath during strength exercises. Breathe out during the effort, and breathe in as you relax.

The hardest part of any lift is the "effort" phase. Applying NIA's rule to common exercises:

The table simply applies NIA's rule: whichever direction takes the most work is the moment to breathe out.

2. Joints: avoid locking them straight

NIA's second technique tip: avoid "locking" your arm and leg joints in a straight position. The moments to watch are the tops of movements, such as standing up out of a squat or pushing up at the end of a push-up, where arms and legs come closest to straight.

3. Warm-ups: the same exercise, lighter

Both sources describe the same warm-up for strength work. The Physical Activity Guidelines say a warm-up for muscle-strengthening activity commonly involves doing exercises with lighter weight, and NIA advises warming up by doing exercises with less weight.

In practice, that means your warm-up looks like your workout, only easier:

• Before squats with weights, do a set of bodyweight squats.
• Before dumbbell presses, do a few reps with a lighter dumbbell.
• Before push-ups, try an easier version you can do comfortably.

The guidelines describe warm-ups and cool-downs in general as doing an activity at a slower speed or lower intensity, and say they are an acceptable part of a physical activity plan.

4. Cool-downs and what they do

For aerobic activity, the guidelines explain the purpose of each: a warm-up allows a gradual increase in heart rate and breathing at the start, and a cool-down allows a gradual decrease at the end. NIA suggests a little light activity, such as easy walking, before and after aerobic activities.

The guidelines add one detail about counting: warm-up and cool-down time can count toward the aerobic guideline, but only if the activity is at least moderate intensity, such as walking briskly as a warm-up before jogging.

5. Where stretching fits

Stretching is often treated as a warm-up, but the official guidance is more careful than that:

• The guidelines say stretching exercises are effective in increasing flexibility, which can make activities that need flexibility easier.
• They also say the health benefits of flexibility activities are unknown, and that it is unclear whether they reduce the risk of injury.
• Even so, the guidelines call flexibility activities an appropriate part of a physical activity program.

NIA's timing advice: stretch when your muscles are warmed up and after endurance or strength exercises, remember to breathe, and don't stretch so far that it hurts.

So a sensible order is: lighter-weight warm-up, main workout, then stretching while you are warm.

6. Learning good form

NIA suggests three ways to learn proper technique:

1. Ask a professional if you are unsure about a particular movement. NIA names your doctor or a physical therapist.
2. Schedule a session or two with a personal trainer, or join a group class at a gym, recreation center, or senior center.
3. Watch demonstration videos. NIA points to its own free online videos of specific strength exercises.

7. Listening to your body

NIA's first safety tip is to listen to your body, and it warns that overdoing strength exercises can cause exhaustion, sore joints, and muscle pain or injury. The Physical Activity Guidelines' broader safety advice adds that people should choose activities appropriate for their fitness level and use appropriate gear, and that anyone with a chronic condition or symptoms should be under the care of a health care provider.

8. Key takeaways

• Breathe out during the effort and in as you relax, and never hold your breath, per NIA.
• Avoid locking your elbows and knees straight.
• Warm up for strength work by doing the same exercises with lighter weight.
• Stretch after your workout while warm; the guidelines say stretching improves flexibility, though its injury-prevention effect is unclear.
• If you are unsure about form, NIA suggests a physical therapist, a trainer session, a group class, or demonstration videos.

This article is general information, not medical advice. Talk with a doctor or physical therapist before starting a new exercise routine, especially if you have a health condition or injury.