Anatomy Of Forearm Training!

The most common mistake within forearm training is thinking that the musculature of the forearms is only responsible for wrist flexion (curling) and extension.
Are you the kind of person to just do wrist extensions and wrist curls and yet you still wonder why your forearms are like twigs with a few veins? The most common mistake within forearm training is thinking that the musculature of the forearms is only responsible for wrist flexion (curling) and extension. As you will see from this article a large and varied number of muscles make up the forearm, which all have differing actions and if you don't include at least some of these movements into your training you will greatly decrease the potential of your forearm growth.

The Usual Suspects

Most people instantly think of wrist curls or wrist extensions when someone mentions forearm training and for good reason, as a large amount of the forearm musculature works during wrist flexion (palm coming towards your forearm) or extension (back of the hand coming towards the forearm).

During the wrist curl three major forearm muscles work - the flexor carpi radialis, the flexor carpi ulnaris and the palmaris longus. All of these muscles originate from the medial epicondyle of the humerus (the bonny lump on the inside of your elbow) and insert down just past the wrist.

To perform the wrist curl position yourself beside a bench so that you can lay your forearms across it with your hands just of the edge and your palms facing the ceiling. Take a barbell in your hands and allow your wrists to bend down towards the floor, pause for a second then bring your hands up until there is nearly a right angle formed between your forearm and hands. Repeat for the desired number of reps.

Wrist extensions work the extensor carpi radialis longus, the extensor carpi brevis and the extensor carpi ulnaris, which all originate from around the lateral epicondyle of the humerus (the bonny lump on the outside of your elbow) and insert into the metacarpals (bones in your hands). To perform the wrist extension, adopt the same position as the wrist curl but have the palms facing down. Once again allow the wrists to bend so that the knuckles end up pointing at the ground then bring your hand back up so your knuckles are pointing towards the ceiling.

Get A Grip

Most people think that most of the actions generated by the hand and fingers are caused by muscles within the hands, yet a large amount of the muscles are actually located within the forearms. This allows the hands their strength whilst also not interfering with the range of motion of all your digits. At this point your probably thinking that most of the muscles will get plenty of work during your pulling motions and you would be partially right, but if you only do minimal grip work you will miss out on serious potential growth of your forearms.

Most authorities on grip strength classify it within three broad terms - crushing, gripping and pinching and it would be wise to train all three types of strength for maximum development. Most people train their gripping strength within the gym when they do pulling movements (i.e. rowing, deadlifting etc). This is do to with gripping strength being defined as the ability to hold onto a weight (a form of isometric strength), yet we know from various studies that strength gains only appear within the range of motion (ROM) that we train in (give fifteen degrees either way). Considering this it would seem prudent to include some thick grip work (thick bar) and some thin grip work (strap holds) to train grip strength throughout the hands range of motion.

During grip work the muscles used are the flexor digitorum superficialis, flexor digitorum profondus and the flexor policus longus, which all originate in up between the elbow and the upper portions of the forearm bones (ulna and radius) and insert down into the thumb or fingers (phalanges), so as you can see they add size to the bulk of the forearm.

To perform thick bar holds wrap a towel tightly around a weighted barbell and deadlift into position. Hold the bar tightly for a given time period and use a weight so your grip starts to fail towards the end (it is sensible to do this exercise in a power rack so that when your grip gives out you don't damage yourself or anybody else). Alternatively you could do your entire regular pulling motions with a thick grip.

On the other end of the spectrum you have thin grip training (strap holds) and you will need a pair of lifting straps. Get hold of either dumbells or a barbell and loop the end that usually goes around your wrist around the barbell or dumbell handles, so that you have a tail effect coming off of the dumbells/barbell. Take hold of the tail and stand up gripping the straps tightly and making sure they do not slip through your fingers and again hold for a timed period. For an alternative to doing standing holds you could perform farmers walks using these types of grips, in which you walk with a set of dumbells for as set distance.

To work crushing strength you will need some form of gripping machine or a set of hand grippers (a good hardcore set is the captain of crush set that can go up to several hundred pounds of pressure). Crushing strength can be defined as the strength required to close your hand against a resistance, so that the fingers work concentrically (positive/closing of the hand) and eccentrically (negative/resisting opening of the hand) against the resistance.

A cheap alternative to grippers is a squash ball, which you can squash in your hand, although the resistance would only be adequate for muscular endurance work. Pinching strength occurs when a resistance has to be held just between the thumb and fingers, this shifts the workload more on to the flexor pollicus longus and the flexor digitorum profundus. To perform pinch gripping effectively you will need to put two smaller plates together so that both sides are flat. Take hold of both plates between your thumb and fingers, once again timed holds work well.

Symmetry of the Hands

You wouldn't train your biceps and not your triceps (at least I hope you wouldn't) and the same could be said for the musculature of the forearms. Whilst the next exercise won't add anything during a symmetry round, it is vitally important for balancing the strength of opposing muscles within the forearm and hand which will prevent potential problems arising (i.e. elbow problems associated with the flexor muscles being too strong compared with the extensors).

Finger extension exercises work the extensor digitorum, extensor pollicus brevis, the extensor indices and the extensor digiti minimi and like the flexor muscles some of these muscles originate in the forearm. The extensor muscles work to extend the fingers (open the hand) and the easiest way of working them is by band extensor work.

To perform band extensions you will need thick strong rubber bands. Take one initially and make a loop around your middle finger to secure it in place. Then place your other fingers around the inside of the band so your fingers and thumbs are all touching (the length of the band needs to be such that when your hand is in this position tension is evident, if it is not you can loop it over again, although this will increase the difficulty). Once in this position you can begin the rep by extending your fingers and splaying them apart simultaneously. The finish position will have your fingers fully extended and fully apart - repeat for the desired number of reps.

Think Laterally

As with all muscle groups performing a different movement (motor pattern) means recruiting the muscle fibres in a different way and helps in creating more intramuscularly co-ordination, which will eventually lead to more gains. Considering all this you should perform some form of abduction and adduction work for your wrists, which means lever bar work.

Lever bar work requires a dumbell rod or pole that weight can be added on one end. For abduction of the wrist (working the flexor carpi radialis, extensor carpi radialis longus, adductor pollicis longus and both the extensor policies brevis and longus) take hold of the pole with the weighted end out in front of you whilst your arm is locked tight into your side. Raise the weight up as far as it goes with your arm staying tight to your side, lower and repeat for reps.

To work the adduction movement of the wrist (working the extensor carpi ulnaris and the flexor carpi ulnaris) perform the exercise whilst holding the pole so the weight is out behind you instead of in front.

Odds & Ends

Various other muscles make up the forearm and hands such as the supinators and pronators, but most of these muscles are worked through curls and such forth. One muscle that adds a reasonable bulk to the forearm is the brachioradialis which causes flexion of the elbow whilst the forearm is in a pronated position (palms facing down), which most people train with either hammer curls or reverse curls. Personally I feel that this muscle gets plenty of work because this is the position adopted in most pulling movements.

All In All

The exercises listed could either be done on one day at the beginning of your weekly split if your forearms are seriously lacking. For most trainees who just want to slightly bring up their forearms the work could be split into two sessions and done after upper body or arm session as so.

Upperbody Workout One Upperbody Workout Two
Wrist curls Lever bar work to front
Wrist extensions Lever bar work to back
Thick grip holds Finger extensions
Strap holds or grippers Plate pinch's

If you are unused to doing grip work you may wish to slowly introduce one or two of these exercises at a time. This especially applies if the days following your session you have to do anything that involves picking things up, such as pens, phones, your toothbrush (i.e. any of you that don't want to be crippled for several days).

As to the sets and reps to be used, most advocate high reps for the forearms - yet I feel the set and rep protocol should reflect your goals. In other words low rep (3-6) work if you are after strength (under twenty seconds for timed hold work), medium reps (6-10) if your aiming for hypertrophy (20-40 seconds for timed holds) and if your aims are for improving muscular endurance and work capacity higher reps should be employed. A couple of sets per exercise will suffice. If your forearms do look like twigs with veins then try this routine for a period. Whilst I cant guarantee that your forearms will look like redwoods with even bigger veins, you should still be pleasantly surprised.


Wirhed 1997. Athletic ability and the anatomy of motion 2nd edition. Mosby

Martini 2001. Fundamentals of Anatomy and physiology 5th edition. Prentice Hall