Muscle Pain, Sprain or Strain...or just plain tired?
We've all experienced the agony of muscle fatigue, but some people immediately jump to the conclusion that 'they've sprained or sprained something.' I even had one of my clients tell me over the phone…my lung collapsed - I can't breathe. Luckily that was not the case! However, the pain of trying to get out of your car, wobble up the stairs, or frequently move after a hard workout is genuine. Post workout soreness is called delayed onset muscle soreness (DOMS), and if you've been exercising long enough, you've probably felt it sometime. Some athletes relish this discomfort, as they see it as an indicator of successful workouts, but is that true?
Why does DOMS occur?
Frequently DOMS occurs after a daunting workout day - whether it is in strength training, circuit training, or hill workouts. It can happen in experienced sprinters, Cross-fitters - or when you've taken a few weeks off. Research studies show (1) that it's not restricted to any particular muscle group, but some people tend to experience it more in specific muscle groups. These are people who are trying to increase their workout volume faster than their body can adjust (2) - more than 10-15% of their volume or weight.
Technical descriptions of DOMS show it is primarily caused by a type 1 muscle strain – and although there is a degree of fiber damage, it is not anything serious. Predominantly it is a result of different exercise that overloads a specific group of muscles after they have been used previously through unusual activity. Some workout sequences do this intentionally, but remember, as you may have experienced DOMS before, there is also a range from slight muscle discomfort to severe pain - both can limit the range of motion. Beware this last situation - you might need to do something about this.
Generally, muscle soreness becomes noticeable about 8 hours post-workout and peaks 48-72 hours later, although the exact course of the recovery process varies. You should also have your muscles reset naturally after a good night sleep and light stretching. Beware muscles that do not recover on their own - this will impact the next workout and push you into ‘potential’ injuries.
For athletes, there is no doubt that DOMS is correlated to exercise-induced muscle damage, whether in not small, or microscopic. Measurement of muscle damage at the microscopic level is poorly associated with reports of soreness. If you're sore, it doesn't mean you completely "shredded" your muscles. MRI images show little damage to some tissues post-exercise, but more to others. Not only does the time progression change with the course of post-workout recovery, but the markers of muscle damage also differ from one another in each muscle. The muscle indicators also don't match the recovery time in the course of muscle soreness reduction (Newham, 1988).
Severe DOMS can develop with little or no indication of muscle damage, and severe damage can occur without DOMS pain. Certain exercise types or workouts can cause significant muscle damage, which is illustrated in the image below - taken after an extensive eccentric (lengthening or stretch) exercise protocol. As you can see, the muscle fiber below look messed up - almost like there is scar tissue developing. The majority of studies examining exercise-induced muscle injuries look at DOMS and how new subjects are injured undertaking large amounts of unfamiliar eccentric (loaded under lengthening) exercises. This model is unlikely to reflect the circumstances of people who workout and experience DOMS pain. It does give us some information into what happens in the muscle when there is a 'breakdown' during overuse.
Muscle image is from an electron microscope after eccentric exercise. Disruption in the muscle pattern tissue is visible. (http://jap.physiology.org/content/107/2/570)
Another DOMS-induced stimulus occurs during exercise tempo or length creates overuse, and high levels of metabolic stress (and this is not the build-up of lactic acid, which does not cause DOMS). When you think that lactic acid causes muscle soreness, this is thoroughly outdated and flat-out wrong. After high levels of exercise, including High-Intensity sessions, rest alone will return blood lactate to baseline levels within the reasonable period required between training sessions. However, evidence shows that hydrogen ions and reactive oxygen – both increase in concentration during exercise – may contribute to DOMS (2) - when the pressure comes from "inside" the cells of the tissue. Metabolic stress during exercise causes changes on the basic level at the cell membrane called the sarcolemma. The disruption in the tissue allows fluids and other factors to enter each cell, which promotes inflammation (3).
Cellular swelling occurs during exercise-induced muscle by bringing fluid and plasma proteins that exceed the capacity of the drainage - which causes the damage. The result is edema in the tissue, with significant swelling lasting ~48 hours post-exercise.
Does DOMS mean more muscle growth?
The presence of DOMS symptoms after long-distance run workout indicates it doesn't just occur during resistance training. The pain is more an indicator that DOMS isn't a good gauge of muscle growth. Running causes minimal hypertrophy and 'muscle build-up.'
People who are new to workouts often have the most pronounced DOMS because they also happen to grow the most. As you can see, the two growth and 'build-up' of tissue damage may be intertwined. This is because of the new stimulus that exercise provides - which is making more tissue based on resistance. When they get sore, it's because they are not accustomed to exercise – not because they are growing like gangbusters. There is no 'sex-based' difference in DOMS, even for beginners (4). There is also a more pronounced 'growth' factor in youth attempting to begin building up, and returnees from a layoff.
DOMS may negatively affect future workouts if they alter movement patterns in subsequent exercises session - based on evidence from highly competitive athletes. Imbalance in the 'muscle group' could cause reduced activation of the desired muscle (5) - the idea is that some 'impaired' potential, doesn't allow the optimum level of development due to imbalance. Hence, DOMS could hinder your next workout. Furthermore, severe DOMS can decrease force capacity by up to 50% (6) due to the lack of 'strength' from edema or extended contraction. This causes functional muscle deficiency, that may impair training at a certain level. Without consistent rest or recovery focus, this could hinder muscle growth over a long term training plan.
Exercise with DOMS does not seem to make muscle damage worse (7), but it may interfere with the recovery process. As you work harder with less effort, there is 'greater' pressure on the muscle tissue. Exercise-induced muscle damage in extreme and isolated cases can cause rhabdomyolysis, a severe condition that can lead to renal failure. As a newbie, don't go into an advanced program – especially if you've never exercised at all. You could do some severe damage.
"No pain, No gain" theory is wrong, when it comes to muscle growth.
How do I feel DOMS?
If the pain you feel isn't the muscles destroying the tissue or burning them up with lactic acid, then why do they hurt? In recent discussions of pain, and this concept is based on how the body 'feels' or registers pain.
Nociceptors are sensory free nerve endings that respond to damage - when stimuli are sending pain signals to the brain. In muscle tissue, the ends of these receptors can sense chemical stimuli like inflammation or disturbances in microcirculation to blood vessels and capillaries. The receptors are not inside the muscle because muscle cell death is not painful, but tearing a muscle tissue can be extremely painful - and the idea to tell the brain of damage when it occurs. The feeling of pain is due to the release of muscle substrates into the space around the 'injury' site, near the nociceptors location. This also helps us appreciate that DOMS does not occur due to something inside the muscle (i.e., like the contractile apparatus) (7) which is sending warnings back to the brain.
How to reduce DOMS?
The best ways to decrease the risk of DOMS symptoms is to slow the progress, vary the repetition for a muscle in a new exercise program - no more than 10-15% increase every week - and increase rest periods. If you've worked on advancing the workout program, you'll notice the first week or two may have reduced volume (either weight or reps). The "intro" phase of programs have two levels: 1) allow the muscles time to adjust to a new movement, and 2) leave room for more adaptative performance.
We all know that warming-up properly will allow improvement in movements and reset neutral postural starting points. Surprisingly, warming muscles don't help reduce DOMS. While it may prepare you for exercise (highly suggested), neither warm-up or stretching before exercise has been shown to reduce or prevent DOMS.
A lot of people use foam rolling techniques to relieve DOMS - or trigger point focus work. However, this has only been shown to improve DOMS in some studies. During compression of foam rolling, you use body weight and gravity on the muscle mass on a foam roller, and exert pressure on an area of soft tissue that is stuck together - or uncomfortable. The motion places a direct burden on any area and stretches the fibers like self-induced massaging because the pressure resembles the compression exerted on muscles by a massage therapist (different angles). Only a few studies have measured the effects of foam rolling on improved performance. These studies found foam rolling enhances the recovery after DOMS by alleviating muscle tenderness. Self-massage through foam rolling can benefit people wanting to recover in an affordable, easy, and time-efficient way.
Another 'muscle tissue' intervention is Myofascial Therapy massage. Some researchers have focused on the decrease in pain associated with DOMS after a massage (8) include breaking apart the adhesion and muscles side-by-side. However, massage does not affect reducing muscle metabolites like glycogen or lactate - except moving them out of the body. One study showed massage decreased the production of the inflammatory cytokines by mitigating cellular stress - or systemic stress from muscle injury (8). Many people believe massage can increase blood flow to specific areas, reduced muscle tension, nervous system levels, and mood enhancement. Some massage techniques produce direct pressure, which may increase ROM and stiffness, and discomfort on overworked tissues can be intense. However, the benefits provided are expected to help athletes and enhance performance in a training plan by reducing the risk of injury. The effects of timing a massage (pre- or post-exercise) on performance, injury recovery, or injury prevention are unclear because the mechanisms of different massage technique have not been widely studied, or compared.
Supplements that impact DOMS
Caffeine is known to increase alertness and endurance, but the average person's morning grumpiness translates into a direct impact on the muscles as well as the brain. A recent study by Hurley et al. reported caffeine reduces DOMS because it increases the circulation and speed at which tissues are affected by changes to the cellular membrane. They measured the perceived soreness in males one hour before a workout and found a lower level of pain in the biceps on day 2 and three. The results were compared to a placebo given to subjects who then completed a bicep curl workout. Using a dosage of 5mg/kg body weight, a beneficial effect of caffeine on soreness was noticed. Comparing, a 185lb (~84kg) male it takes about 420mg of caffeine pre-workout. That is a ton of caffeine - when an 8oz Red Bull contains roughly 85mg. Most pre-workout supplement levels don't have that much caffeine, do they? Probably not. If caffeine peaks in the blood, about one-hour post-ingestion, that's a lot of pre-workout liquid. Caffeine is an adenosine antagonist and affects the activity of the central nervous system (CNS), and it blocks the adenosine receptors, resulting in decreased levels of soreness - or lack of receptive activity. Therefore short-term caffeine ingestion before a strenuous workout may reduce the overall level of pain. However, the athletes who took caffeine were able to perform more reps than the control group, which could be a disrupter of the results.
Taurine is found in muscles and has multiple biological functions. If you remember the energy drive Red Bull I mentioned earlier, it has about 1,000mg of taurine - as well. 3,000mg a day of supplemental taurine is considered safe. In one double-blind study (10) of males completed over 21 days - they measured the effects of 50mg of taurine (20x less than the content in a Red Bull) after seven days of eccentric exercise protocols. The researchers found a reduction in DOMS and oxidative stress markers with use. There was no effect on inflammatory markers - or the cellular changes mentioned in the first part of the article.
But it would be interesting, as oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and non-enzymatic antioxidants. Biomarkers of oxidative stress are relevant in the evaluation of the disease status and of the health-enhancing effects of antioxidants. In conclusion, the clinical significance of biomarkers of oxidative stress in humans must come from a critical analysis of the markers that should give an overall index of redox status in particular conditions. If inflammation is one component to DOMS and oxidative stress is another component, we need a study to combine the two. That probably won't happen soon to use a synergistic review.
An omega-3 fatty acid is found in fish and is increasingly used to fortify foods. EPA/DHA can be found in those pills that make you burp continuously. Several studies reporting definite increase with the effect of omega-3 fatty acids on DOMS assumes that there was a decrease in pro-inflammatory factors such as IL-6 and TNF-alpha as well. There are a ton of studies to show taking an omega-3 supplement is right for you in many ways. These results seem to hold for DOMS as well, see the effects, the main table from Jouris et al. 2013 below.
Other Variable Recovery Activities
Cryotherapy, or icing on the muscles, probably doesn't reduce DOMS. Directly against the current assumption of athletes - jumping in a tube surrounded by liquid nitrogen to help recovery - this is related to the slowing of the whole recovery process. Whole body cryotherapy exposes athletes to cold, dry air below -100C for between two and four minutes in a specialized chamber. A recent Cochrane Review by Costello et al. found insufficient evidence to determine whether cryotherapy can reduce muscle DOMS or improve recovery process only by decreasing the ambient temperature of ALL muscles.
No guidelines currently exist for its clinical effectiveness or safe usage. Cryotherapy is thought to work by reducing the temperature in the skin, muscle, and core at once. The theory assumes that muscle soreness, and inflammation increase created by muscle activity, is relieved by reducing muscle metabolism, skin microcirculation, nerve conductivity, and receptor sensitivity. There could be a placebo effect by reducing the subjective feeling of DOMS post-exercise - only by lowering the level edema in the cells (i.e., less pressure on the cellular membrane). Using a meta-analysis based on four studies shows cryotherapy does not reduce DOMS or improve recovery.
Additional evidence exists on whether cold water emersion -post-exercise can decrease the rate of muscle growth. For the time being, focus on
Soreness provides insight, but don't use it as a marker for a good workout progression. High levels of pain indicate the muscles have exceeded the capacity for the tissue to undergo repair in an organized manner. Indeed, soreness can impede the ability to train correctly, especially if it impacts sleep and 'proper movement and posture,' and it may decrease motivation.
Research consensus is that there is no single component that causes DOMS. Instead, several complex events may explain this phenomenon, creating an impact on exercise performance and recovery that include decreased muscle strength and range of motion. There should be several factors that help increase the 'good effects' of works - and reduce the impact of symptoms like DOMS.
1) Drink Lots of Fluids and Hydrate
Any fitness guru knows the importance of proper hydration prior, during, and after an intensive dose of physical activity. Hydration will support increased circulation and movement of nutrients throughout the body.
2) Good, restful sleep
With plenty of rest, as a key to both mental and physical health, lack thereof is also unfortunate. Lack of it can significantly hinder not only the course of muscle recovery but also your overall athletic performance because all natural body processes are negatively impacted by lack of sleep. According to a 2008 study, sleep deprivation is detrimental to recovery and inhibits the body's natural processes.
3) Focus on Your Protein Intake
Protein is the number one muscle repairing nutrient in your diet. Instead of adding supplements to your smoothies, focus on getting your daily intake of protein from whole foods such as eggs, Greek yogurt, cottage cheese, and lean cuts of meat. These versatile ingredients make great snacks or full meals - ensure that they are used throughout the day to help with your recovery.
Also essential is consuming a snack rich in protein before bed so that your muscles repair over time. The essential amino acids that are metabolized from this macronutrient are vital to rebuilding tissues.
4) Plan Your Rest Days Accordingly
When it comes to rest days, the general rule is to maintain a healthy gap of 48 hours - and with fans of more physically demanding routines. Of course, this is instead a guideline that you can tailor to suit your personal needs and preferences.
Never forget the stretching, especially during recovery days. This habit will help with your muscle recovery, and won't burden the tissue any longer than necessary - and will remind the muscles of their neutral length and flexibility.
Depending on your age and skill, you might require less time to rest or more. Taking longer pauses will allow you to try to squeeze in a couple of active recovery days each week. These days consist of light exercises, such as yoga or tai chi, actual muscle release can also help you stay on track to fitness goals while relaxing and recharging your muscles at the same time.