Delayed Onset Muscle Soreness (DOMS) is a condition of muscle pain, soreness or stiffness that is generally experienced  12-48 hours post exercise.  It is particularly prevalent when kicking off a new program, switching disciplines ( trail running to kayak for example ), or after shifting your volume and intensity up a notch or two or doing compound sessions such as bricks.

Contrary to old wives tales and dated wisdom, DOMS is not caused by lactic acid accumulation after a tough training session or race. Szymanski (2001) notes that blood and muscle lactate levels do rise considerably during intense eccentric and concentric exercise, however values for blood and muscle lactate return to normal within 30-60 minutes post exercise. Szymanski also notes that the symptoms of DOMS peak within 24-48 hours after an intense eccentric exercise bout when blood lactate levels have been at normal levels for a considerable amount of time.

DOMS is often triggered mainly by eccentric exercise, such as downhill running, plyometrics, and resistance training. Connolly et al. (2003) explain that the injury itself is a result of eccentric exercise, causing damage to the muscle cell membrane, which triggers an inflammatory
response. This response in turn initiates the formation of metabolic waste that chemically stimulates the nerve endings; causing pain. The metabolic waste products act to increase vascular permeability and attract neutrophils (a type of white blood cell) to the area of micro-trauma where they then proceed to produce nasty free radicals (molecules with unshared electrons), which are infamous for adversely affecting the cell membrane.

You will often see swelling around membrane injury. As opposed to clinical injury to a muscle, a muscle that is subjected to DOMS, still enables eccentric exercise without risking additional muscle damage.

Both Connolly et al.(2003) and Szymanski (2001) agree that typical symptoms often associated with DOMS include strength loss, pain, muscle tenderness, stiffness, and swelling. Loss of strength usually peaks within the first 48 hours of an exercise bout, with full recovery taking up to 5 days. Pain and tenderness peak within 1-3 days after exercise and typically subside within 7 days. Stiffness and swelling can peak 3-4 days after exercise and will usually resolve within 10 days.

There is no clear, concise integrated program of intervention to treat DOMS comprehensively. Too many of us succumb to a quick fix use of a generic Nonsteroidal anti-inflammatory (NSAIDs) compound such as  such as aspirin or ibuprofen. Unfortunately, research done on NSAIDs efficacy has turned up a hotch potch of often contradictory results. Well documented negative side effects from NSAID use, particularly gastrointestinal reactions, and hypertensive effects tend to ward us off using these.

Naturally enough, because DOMS is a product of sudden (relative) increases in exercise regime or type as you gradually increase the new load the body will adapt. Szymanski states that the repeated bout effect of continued gradated load is proposed to allow for a faster recovery of strength and range of motion in effected muscles, providing for increased resistance to damage after the first bout. It is also thought that muscle and connective tissue gradually adapt to increasing intensities of eccentric exercise, minimizing incidence and severity of DOMS.

A simple and effective preventative measure to adopt in combating DOMS is straightforward’ thorough, well planned and executed warm-ups. In effect, these routines can be placed into two categories, general and specific. General warm-up is aimed at increasing core body temperature by performing movements that require the use of large muscle groups, such as calisthenics and running. Specific warm-up, mimicking the movement patterns of the actual exercises, is aimed at increasing the local muscle temperature in the muscles, which will be used in the specific discipline. It is  generally more effective  to precede an intense exercise bout with an adequate general and specific warm-up. Warm-up duration can vary greatly, depending of the intensity of physical activity, environmental conditions, and fitness level of clients (less fit people or those recovering from injury or illness may need a longer warm-up).

Post-exercise strategies are a mixed bag but rest, RICE, massage, yoga are the most prominent.