First I'll need to address the Gate Control Theory as most therapeutic modalities work via this mechanism. Essentially it allows the CNS to override a painful stimulus.
Lets say you have Stimulus A (pain). You then provide Stimulus B (ice, heat, stim, rubbing the injury with your hand) The new stimulus takes priority and the pain decreases or goes away. Yes its that simple.
Ice. Seriously if I need to explain that it doesn't reduce inflammation you're NGMI. It delays inflammation which is essential to the healing phase. It therefore delays healing.
Ice causes vasoconstriction which means the blood vessels get smaller. This leads to less blood flow. It takes approximately an hour for the tissue to warm up. "But Kobra, what about the Hunting Effect?"
The Hunting Effect is a phenomenon in which there is a rebound vasodilation after the vasoconstriction. If you need to decrease blood flow to then increase blood flow you hate optimization.
However, Ice is a very good analgesic (reduce sensation) as it provides a new stimulus via gate control. If you absolutely need to reduce pain and have no other option then it will work in that capacity. Just know it will slow you down.
Next up is heat Heat works in the opposite capacity. The body has to vasodilate to try and reduce overall temperature. This leads to more blood flow (always a good thing)
Same as with ice, heat reduces pain via gate control. The limitation with heat is that it is very superficial. 15 minutes of a hot pack only reaches a tissue depth of 1 cm. Good luck if you wanna heat anything remotely deep.
For the proper therapeutic properties of heat (decrease spasm, decrease pain and increase blood flow) the tissue needs to be heated by 3.6 degrees F. In actual application a hot pack can only achieve this temperature at superficial depths.
As you can see from the image above, heat will rarely have the therapeutic benefit you want in the tissue you want. Hot packs will almost always fall short of their therapeutic goal. You could simply go for a walk and warm up the tissue properly.
Moving on to electrical stimulation. This works purely via gate control theory. There are no other biological processes happening here. Stim will work very well to reduce pain.
The pain relief is very temporary (30 minutes or so) and does not fix any underlying issue. It is purely a Band-Aid for the injury. It also is a terrible ROI in terms of time. A single treatment will take 20 minutes to net 30 minutes of pain relief. Not efficient
If pain is your biggest concern, then stim can provide relief. If getting better is your biggest concern, stim will not help. It won't hurt either; it will just waste your time.
We'll continue this thread next week with ultrasound and laser As always let me know if you want to see something or want further explanation.