Working up to your Activity Threshold

Written by Jessica Moss on February 5, 2018.

I often ask people how a muscle feels when performing a particular movement. The response can be anything from “It hurts, I can’t keep doing this!” to “I don’t know, I can’t tell!”. Since I am not inside of your body and I cannot feel exactly the same thing that you are, it is difficult for me to judge what you are feeling or how difficult a movement is for you. So, I thought it might be helpful to discuss the specifics of training in order to give you some concrete ideas about what is going on inside of your body.

In order to become stronger and more mobile your body needs to work harder than it normally does. Working harder refers to an activity threshold, a point where the body is pushed to a level where fitness gains occur. According to The American Physical Therapy Association, everybody has an activity threshold. If you work up to your activity threshold, then you will feel muscular soreness and your strength will increase. If you push past your activity threshold, the result will be pain and possible injury. When you work up to your activity threshold at each session, over the course of a few weeks, that threshold will increase and you will be able to work harder, do more sessions per week and/or work longer during each exercise session.

This grid from APTA, may give you some guidance about what to do when feeling specific types of discomfort either during or after a workout.

	Muscle Soreness	Pain
Type of discomfort:	Tender when touching muscles, tired or burning feeling while exercising, minimal dull, tight and achy feeling at rest	Ache, sharp pain at rest or when exercising
Onset:	During exercise or 24-72 hours after activity	During exercise or within 24 hours of activity
Duration:	2-3 days	May linger if not addressed
Location:	Muscles	Muscles or joints
Improves with:	Stretching, following movement	Ice, rest
Worsens with:	Sitting still	Continued activity
Appropriate action:	Resume offending activity once soreness subsides	Consult with medical professional if pain is extreme or lasts >1-2 weeks

Muscle soreness is an expected part of physical activity and strength training, however it is sometimes difficult to tell the difference between normal, exercise-related soreness and pain that is a result of injury. Certain sensations are signs of injury other types are simply a result of normal changes in the muscle which occur with increases in exercise or training. Trying to be aware of the difference between muscle soreness and muscle or joint pain will go a long way toward making your exercise sessions productive and fun.