‘Good’ vs ‘bad’ pain: How to tell when your body is saying 'no' while exercising

Fitness First Singapore’s Christine Chiam agreed. “While we push ourselves to become fitter and stronger, pain is an abnormal symptom,” said the fitness training manager. “Work within your comfort levels as it is more important to stay safe and injury-free than to feel the peer pressure and over-exert,” she said.

Aqil Zainal, a strength and conditioning expert from Evolve MMA, is another trainer who agrees that pain is a red flag. "If you do your exercises with proper form, sufficient bracing and control, a certain level of soreness may be acceptable. But there shouldn’t be pain, especially unbearable pain or discomfort."

WHAT HAS RHABDOMYOLYSIS GOT TO DO WITH OVER-EXERTION?

Not listening to the body could have contributed to the cases of rhabdomyolysis that you have read in the news. The painful condition, which affects overworked muscles, “is fairly common but underdiagnosed” in Singapore, said Adjunct Assistant Professor Endean Tan, a consultant in general medicine at Tan Tock Seng Hospital. “My team has seen about five such cases in the past month alone.”

In fact, of the last 20 rhabdomyolysis patients Adj Asst Prof Tan has seen, spinning has been responsible for 19 of them, he said. “Only one case was a young man who went for a 10km run without prior preparation.”

Dr Sean Leo, an orthopaedic surgeon at Mount Elizabeth Novena Hospital, too, has noticed individuals in their late 20s or 30s developing rhabdomyolysis after spin classes.

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So what exactly is rhabdomyolysis and why is it linked to spinning?

"Rhabdomyolysis is the excessive breakdown of muscle cells, which results in the release of their components into the blood stream, many of which are directly toxic to other cells and particularly, the kidneys,” said Adj Asst Prof Tan. 

There will be muscle weakness, pain (even when you are not moving the affected muscles) and dark urine produced. It is a serious condition that requires immediate medical help, he said.

As for the recent connection between rhabdomyolysis and spinning, it could be the popularity of time-saving, high-intensity exercises that include said spinning as well as high-intensity interval training or HIIT programmes, said Adj Asst Prof Tan. 

"The idea of a quick fix with respect to fitness is a great draw, and it fits well with our very busy lifestyles," he said. Indeed, indoor cycling has been found in studies such as this for promoting weight loss and raising HDL or "good" cholesterol levels.

READ: Does walking 10,000 steps a day really help in your weight loss efforts?

However, these high-intensity sessions could put you at risk of rhabdomyolysis if you have been sedentary. Other factors include an increased age, poor hydration, pre-existing medical conditions (for example, hypothyroidism and diabetic ketoacidosis) or individuals on medications such as statins, antihistamines and salicylates. 

HOW MUCH EXERCISE IS TOO MUCH EXERCISE?

To help you make better decisions about your workout intensity (rather than hide behind excuses such as "Oh, I have a bad knee"), it helps to be able to differentiate between “good” and “bad” pain. 

Good pain is usually muscle soreness (also known as delayed onset muscle soreness or DOMS) that you might experience when you’ve just embarked on a fitness programme or a new training stimulus, said Joan Liew, a personal trainer and co-founder of Fitness Factory. “DOMS starts about six to eight hours post-exercise, and peaks between 24 and 48 hours after your session,” said Liew.

Typically, the soreness would clear up within one to three days, and the body will get stronger as it starts to adapt to the training, she said. If the same exercise intensity is performed again within the next one to two weeks, she explained, the muscle soreness should not recur; if it does, the soreness will be at a significantly lesser degree.

But how sore should you expect to feel after a workout? Liew said a good rule of thumb is anything between one and four on a scale of 10, where 10 is the worst pain imaginable. “Anything above that, or if you actually experience pain that changes your gait pattern, is an indication that the intensity of your previous activity was very high,” she said.

On the other hand, “bad” pain is pain experienced in the joints during or after the workout session, said Liew. For instance, there is a difference between the muscular “burn” during a squat and actual pain in your knees.

“This is a sign that you should stop and assess the pain,” advised Liew. “If your personal trainer still insists that you push through the pain, despite repeated feedback that the exercise is too much for your joints, he or she is over-pushing you and is not worth your time and money,” she said.

Another way to gauge whether you have over-exerted yourself is how you feel when you walk into the gym or studio, said Aqil. "If you arrive without the motivation or focus but with the feeling of soreness or fatigue before even starting, that may be a sign that you are under recovered." 

During training, if there is a significant dip in performance or a constant discomfort, that is also a sign that you have over-trained, he said. Observe changes, too, such as a reduced appetite, weight loss and sleep quality as these are other red flags that you have been over-pushing yourself, he added. 

To help you gauge your intensity level, Chiam recommends using the rate of perceived exertion (RPE) scale – and it works even if you don't own a heart rate monitor. Simply rank the effort that you put in on a scale of one (sitting in a chair) to 10 (maximum effort). 

For instance, she said, a light evening stroll would measure two or three on the RPE scale. Moderate activities (for example, a light jog) is about four to six, while vigorous activities such as sprinting is rated seven to eight. “If you are new to exercise, start at RPE three to four, and gradually build it up. Most group classes are at least RPE six to seven,” she said.

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Explained Aqil: "The RPE scale is useful as it is not recommended to have hard sessions back to back. Having low RPE training sessions in-between high RPE sessions would not only help your body recover, but also allow time for adaptions to the body, which is essential for muscle growth and strength".

HOW DOES OVER-EXERTION AFFECT YOU?

Besides rhabdomyolysis, there are other injuries that can come from over-exerting yourself. Find out what they are in the common workout scenarios below and what you can do to minimise them:

• Hiking

Taking on the Rail Corridor may seem easy-peasy as the trail is largely paved (no different from strolling in the park, right?). But if you cover too much ground too soon, you may be setting yourself up for “muscle and tendon strains of the back or lower limb, or joint pains such as runner’s knee”, cautioned Dr Lim. And if you have osteoarthritis, you can expect pain in the affected joints.

Warm and humid conditions can increase your risk of rhabdomyolysis and exertional heat injuries. “Pick a time to do your hiking when the temperatures are cooler, such as earlier in the morning, and aim to finish before the afternoon," suggested Dr Leo.

• Running

Both long-distance running and sprinting have their shares of injuries if you suddenly decide to put on your running shoes without prior training or conditioning. 

Other than rhabdomyolysis and heat injuries, “a sudden increase in running volume, as well as inadequate footwear, can result in stress fractures in the lower limbs,” said Dr Lim, adding that pushing too hard to cross the finish line, especially when untrained, could cause a sudden cardiac event or even sudden cardiac death.

Meanwhile, sprinting may result in hamstring tendon and/or muscle tears if you are not trained, or have underlying issues such as hamstring tightness or previous untreated hamstring injuries, said Dr Lim.

To prevent overuse injuries, mix running with other forms of strengthening exercises to reduce injuries – and increase your endurance, too, said Dr Leo. Pre-run stretching exercises are also important as they “decrease the risk of joint, ligament and muscle injuries”, he said. 

“Should you experience pain from the joints or muscles, decrease your pace to see if the pain goes away and stop completely if the pain persists.”

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• Swimming

Being proficient in your stroke is important, said Dr Leo, as both the upper and lower limb joints are subjected to constant motion when you’re swimming. Furthermore, the range of motion is large, especially in certain strokes such as butterfly and freestyle, which can increase your risk of injuries, he said.

Injuries of the shoulder rotator cuff tendons may occur with over-exertion, said Dr Lim. In breaststroke, the knee ligament may be prone to injuries due to the extensive kicking, she said.

READ: From CrossFit to HIIT: Are you at risk of injury at your overcrowded gym?

• High-intensity interval training or HIIT

With the high-energy music and everyone giving his all, it is tempting to try to keep up. Whether it’s hitting the number of burpees on today’s workout plan, or pushing yourself to last the final 10 seconds of high-resistance pedalling, there’s a high chance you may “not focus on the correct technique and form of each action”, warned Dr Lim. "The risk of injury further increases with fatigue."

She continued: “This can result in muscle, tendon, ligament or joint injuries. Certain workouts include rapid changes in direction, such as twisting activities in the knee, and these may result in injuries to the ligaments, meniscus injuries, or even kneecap dislocations".

Chiam, who is also an HIIT instructor, said to look out for these signs if you suspect rhabdomyolysis: Sharp pain, dizziness, difficulty catching your breath, and excessive muscle fatigue. 

“See a doctor if you experience signs and symptoms of severe exertional injury such as thigh or calf swelling or pain, which are commonly seen in patients presenting with rhabdomyolysis," said Dr Leo.

• Yoga

Should your yoga teacher be physically pushing your body into the intended pose during class? There is no right or wrong yoga practice, according to Gajendra Badwal, the founder of Align Studio. 

For instance, there is a "very regimental military" practice where teachers "often exert pressure on their students and believe that everyone should be able to fit in all yoga postures, no matter what". There are also teachers who "recognise that everybody is unique and different" and guide students to progress at their own pace, said Badwal.

Decide what works best for you, he advised. "If you don't like your teacher to exert pressure on your body, find someone else to go to, or other yoga classes or studios where you can find the culture and practice that you vibe with."

As for discerning if the pain is too much, the challenge is to discern which pain you are experiencing, said Badwal. To simplify it, think of "good pain" as a sensation that feels like your soft tissues are pulling away from your joints, like when you're stretching your muscles. Bad pain is felt close to the joints and should be avoided, he said.

"If I have to give you a number on a pain scale of one to 10, anytime you find yourself fighting with a pain above seven, ask yourself: Why are you doing it? What is the intention and what good does it to your body and mind?" said Badwal.

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• Weight training

Jeannie Wang, a strength training instructor with Fitness First, said that sharp pain and/or pain not at the working muscles is a sign to stop or ease off by switching to a lighter load. “Shoulder, knee and spinal issues are common if one carries too heavy a weight and forgo the technique,” she warned. 

If you’re new or have just returned to your routine, Chiam suggested using a three to five repetitions in reserve (RIR). “This means that for the weight you’re using, you could have done an additional three to five more reps. This allows for a safer way of training and an emphasis on technique as opposed to just loading,” she said.

Other than increasing your load and repetitions progressively, it is also crucial to have adequate recovery time in-between sessions to prevent over-use injuries, said Dr Leo.

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• Shadow boxing

It’s not like you are punching or kicking anything, so what do you have to lose? “Without a target to punch or kick, there is a risk of hyper-extending the joints, causing strain to the muscles, tendons and ligaments,” said Wang. There is a risk of pain in the joints from uncontrolled kicks and punches, she said.

Long and high-intensity sessions can also cause “significant strains on the joints, muscles and shoulders”, said Dr Leo. “Boxing while one is exhausted will result in more injuries, so it is important to space out your exercises and allow adequate recovery time.”

Consult your doctor before starting any fitness programme. See a doctor early if you suffer from any pain as a result of training.