(Photo source: teddy-rised)

How heavy are your grocery bags?

Walking home with bags of groceries is a common activity but is the load giving you wrist pain? You have multiple bags in your hands. You may not realise, but you are easily carrying 10 – 20 kg of groceries on each trip to the wet- or super-market. If you walk about 200 metres to your home, the trip is equivalent to a short but intense workout for the arms, wrist and fingers. 

You are walking but the bags barely sway in your hands. When goods are being transported in a lorry, the goods are secured with ropes and carabiners so that they won’t topple over when the lorry is moving. What is keeping the bags balanced in your hands as you walk?

To understand the cause of your wrist pain is to take a closer look at the bio-mechanics of the wrist and fingers. Which wrist and finger muscles are recruited when you carry a bag of grocery? Why do wrist and finger muscles become tight and painful?


In order to carry a bag of grocery without dropping, we need to wrap our hand and fingers around the bag’s handle. The action requires flexion at the wrist and finger joints. The flexor muscles of the wrist and fingers have to contract or shortened for wrist and finger flexion to occur.

What about the extensor muscles of the wrist and fingers? Are they active? The extensor muscles, the opposing muscles of the flexors, are also in contraction. But their job is to stop the flexor muscles from over-recruitment. The extensor muscles act like brakes or a circuit-breaker to the flexors to keep them in check.

A balancing act between the flexor and extensor muscles of the wrist and fingers.

(Photo source: tawakilagi.com)

So the flexor muscles are the prime movers, while the extensors are in supporting roles. The flexors and extensors are constantly adjusting in relation to each other as you move. It is a balancing act between the two opponents, so that the bags of groceries remain in steady in your hand.

Unfortunately, most of our daily activities require the flexor muscles of the wrist and fingers to be the prime movers. Typing, turning on a tap and holding a cup or a screwdriver or a gardening tool are other common day-to-day activities that require flexion at the wrist and finger joints. Overtime, the flexor muscles become stronger than the extensor muscles which create a muscular imbalance.


Wrist pain or injury occurs when you task the extensor muscles of the wrist and fingers to be prime movers. People often hurt their wrist when they have to put down a heavier-than-usual object like a fully packed luggage bag or a flower pot, for example. The extensor muscles don’t have the strength or practice to extend the wrist and fingers to put down the heavy bag or pot. The extensor muscles are more familiar playing the supporting role to the flexor muscles.

Additionally, as the hands are often held in flexion which shortens the flexor muscles of the wrist and fingers, the flexor muscles are strong, but they lack the range of motion to execute an activity that requires full wrist and finger extension. The result is wrist pain or worse, an injury.


You may feel pain when rolling the wrist or when extending the wrist and fingers to put down an object. The pain is felt on the palm (carpal tunnel syndrome) or one or more of the fingers (trigger finger.) Other symptoms include pain and loss of sensation on the finger tips (phantom pain,) and referral pain on the elbow, neck and shoulder.

Why that numbing sensation on the fingersWhy do the fingers feel numb?

The brain controls the actions of the body via the nervous system. The body’s nervous system works like a good communication channel. It keeps the brain wired to the rest of the body.

When you want to carry the bags of groceries in your hands, the brain sends signals — en-route the spinal cord — to the nerves of the wrists and fingers. They tell the wrist and finger muscles to pick up the bags.

The nerves in our hands and fingers are also responsible for giving us a sense of touch. You feel cold when holding an icy drink in your hand, and pain when you are pricked by a needle.


The flexor and extensor muscles of the wrist and fingers are en-nerved by the median and ulnar nerves. When the flexor muscles of the wrist and fingers are over-active and short in length, they can compress the median and/or ulnar nerves. When this happen, it interrupts the flow of signals from the brain to the hands and fingers.

Symptoms of a nerve impingement are numbing sensation on the hands or fingers, loss of grip strength, as well as associated pain on the neck and shoulders.


However, not all numbness on the hands and fingers are caused by muscular imbalances. Peripheral neuropathy refers to a condition where the nerves on the hands or feet are either damaged or impaired by an injury to the feet or hand, an infection or a disease that attack the body’s auto-immune system.

Diabetes, and chemotherapy medication in the treatment of cancer are also known causes of peripheral neuropathy.

Symptoms include a loss of sensation on the fingers and toes. An example is the inability to feel the floor when you walk.


Manual therapy and stretching help loosen the flexor muscles of the wrist and fingers, which have become over-active and short in length. They are followed by exercises to strengthen the extensor muscles. Training the extensor muscles to be prime movers, so they are as strong as the flexors restore balance to the muscles of the wrist and fingers.

When opposing muscles of the wrist and fingers are equally strong, the pain would dissipate. There is also less chance of a recurrence. There are many manual or physical therapy techniques, as well as different stretching methods. Manual therapy and stretching are highly beneficial for pain relief, but the relief is often temporarily. For pain relief to be more lasting, exercise is a must-have in pain treatment. Re-training the muscles of the wrist and fingers, including changing the balance of strength with specific exercises, offer a more long-term solution.


There are many health benefits as to why we should exercise regularly. Regular exercise improves cardiovascular health, and lowers the risk of metabolic diseases like Type II diabetes. Although not as well known, exercise can also provide pain relief. Recent studies have shown exercise is a good source of relief for back pain.

Most common aches and pain — though not always — are caused by some form of muscular imbalance. For example, you spend a good part of your day at work, typing; and you are also responsible for your family’s grocery shopping. Both activities make the flexor muscles of the wrist and fingers more active than the extensor muscles. If you have wrist pain, both activities are likely contributing factors to the pain.


Fortunately, our musculatures are highly capable of adaptation and change. We are designed for movement. As with any physical activity, adaptation and change involve Effort. To see a physiological change, you would need to stay with the exercise over a period of typically eight to 12 weeks.

Remember the opposing muscles are also active in every action. If you are training the extensor muscles to be better movers, you are also training the flexor muscles. You are teaching them how to better support the extensor muscles. Don’t be surprised to feel less tired the next time you carry the bags of groceries. Start today. Sign up for a Move Therapy or Pilates session. Exercise your pain away.

Medical Disclaimer: Always consult your physician if you have an existing pain or a pre-existing medical condition before beginning any exercise. The above information is not intended to diagnose any medical condition or replace your healthcare professional.

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