RECOVERY – after exercise, can we reduce our soreness through heat or cold? What is more effective?
Cold vs. heat after exercise – is there a clear winner for muscle soreness, by Petrofsky, Khowailed, Lee, Berk, Bains, Akerkar, and Laymon, in Journal of Strength & Conditioning Research (2015)
Delayed onset muscle soreness (DOMS) is frequently experienced by athletes and recreational trainees when exposed to either novel resistance-training workouts or a large volume of eccentric muscle actions. Symptoms include soreness, tenderness upon palpation, and stiffness during movement. DOMS appears to occur reliably between 12 – 24 hours post- workout, with soreness peaking around 48 hours post- workout. There is a lack of consensus regarding the underlying mechanisms that cause DOMS. Some researchers consider DOMS to be caused entirely by exercise-induced muscle damage (EIMD). EIMD is similarly characterised by muscle soreness, muscle swelling, an increase in intramuscular protein and passive muscle tension, and also involves a reduction in muscular strength and range-of-motion. In this model, EIMD causes various disruptive changes, including sarcomere damage, calcium accumulation, protein degradation, and increased osmotic pressure.
These changes lead to the sensitization of nociceptors and other pain receptors, which leads to the sensation of DOMS being experienced. A number of different interventions have been tested for reducing both EIMD and DOMS. There is some evidence to support the use of massage and limited evidence to support the use of self-myofascial release with a foam roller. The mechanisms by which massage or self-massage might be effective for reducing DOMS are not well- understood and various possibilities are currently being explored by researchers. One interesting feature of DOMS is that it is dramatically reduced when the muscle has been exposed to a similar stimulus on a recent, previous occasion. This is known as the “repeated bout effect” and indicates that central factors may well be involved in addition to local ones.
OBJECTIVE: To compare the effects of applying either cold or ThermaCare heat wraps either immediately or 24 hours post-exercise on muscle soreness (measured using a visual analog scale [VAS]), leg strength and passive stiffness (as measured by knee flexion and extension force using a strain gauge) and myoglobin.
POPULATION: 100 healthy subjects, randomly allocated into 5 groups: (1) control, (2) cold pack immediately post-exercise, (3) cold pack 24 hours post-exercise, (4) heat pack immediately post- exercise and (5) heat pack 24 hours post-exercise.
INTERVENTION: All subjects performed an acute protocol of squat exercise that was intended to cause DOMS. This protocol involved 5 minutes of continuous bodyweight squats with 1 squat performed every 3 seconds. This was repeated for a total of 3 sets with 3 minutes of inter-set rest. Where subjects were allocated to either cold packs or heat packs, these were applied at the designated time post-exercise or at 24 hours post-exercise. Cold packs were applied for 20 minutes at the designated time but hot packs were applied for 8 hours starting at the designated time.
The researchers observed that the control group displayed a temporary 24% reduction in leg muscle strength at 24 hours following the DOMS protocol. At 24 hours, the reductions in strength observed in the cold (immediate) and hot (immediate) groups were significantly less than that in the control group but there was no significant difference between either the cold (immediate) and hot (immediate) groups. After 3 days, strength reductions were still present in the cold (immediate) but not in the hot (immediate) group. At all time points, the reductions in strength observed in the cold (24 hours) and hot (24 hours) groups were significantly less than that in the control group but there was no significant difference between either the cold (24 hours) and hot (24 hours) groups.
Muscle soreness and myoglobin changes
The researchers observed that all groups displayed an increase in muscle soreness (as measured by VAS) that peaked at 2 days post-exercise. At 24 hours, there was no significant difference between the cold (immediate) and hot (immediate) groups. At 3 days, VAS increases were lower in the cold (immediate) than in the hot (immediate) group. Similar results were observed in respect of the cold (24 hours) and hot (24 hours) groups. The researchers also observed that all groups displayed an increase in myoglobin post- exercise but there was no difference between groups.
What did the researchers conclude?
The researchers found that cold application appears to be superior to hot application for reducing DOMS but hot may be superior for reducing strength loss.
The study was limited in that the post-exercise and 24 hours post-exercise conditions were not compared.