Hand Forearm Blaster

A hand forearm blaster is a resistance exercise machine, which involves finger flexion to improve grip strength. This exercise is performed seated or standing, depending on the type of machine, with hands wrapped around two parallel rods.

The concentric portion of the lift is finger flexion, which involves the lifting of the weight/squeezing the two rods together. The eccentric portion is finger extension, which involves the descent of the weight/separation of the rods.

The purpose of the hand forearm blaster is to strengthen the finger flexors, which strengthens grip and promotes hypertrophy (increases in size) of the forearms.

Resisted finger flexion performed on a hand forearm blaster strengthens and increases the size of the finger flexors. Increasing the size of the finger flexors complements the aesthetics of the forearms as some of the finger flexors’ tendons and muscle bellies originate at and extend down the forearm.

Engaging the primary finger flexors, flexor digitorum superficialis, flexor digitourm profundus and adductor pollicis, improves grip strength performance. This translates to enhanced grip that can benefit overall weightlifting performance and athletic performance for particular sports (e.g. equestrian, baseball, powerlifting, Strongman, jiu-jitsu) .

The primary finger flexors, flexor digitorum superficialis and flexor digitorum profundus, are located on the front of the forearms with their origins on the medial side of the elbows (with palms facing out, the side of the elbow closest to your body). Their insertions are located at the hands. The other primary muscles involved in this exercise are the adductor pollicis, lumbricals, palmar interossei and dorsal interossei, which are intrinsic muscles of the hand.

The flexor digitorum superficialis is a two-headed muscle that is located under the flexor carpi radialis and flexor carpi ulnaris. It originates at the medial epicondyle of the humerus, the coronoid process of the ulna and the shaft of the radius. It inserts by four tendons into the middle phalanges of all fingers except the thumb.

The flexor digitorum profundus, as its name suggests, is a deep muscle, located underneath the flexor digitorum superficialis. Its origin is located at the anteromedial surface of the ulna and at the interosseous membrane (located between the ulna and radius). Like the flexor digitorum superficialis, the insertion of the flexor digitorum profundus inserts by four tendons into the phalanges of all fingers except the thumb, but at the distal portion of the phalanges (further down the finger bones).

The adductor pollicis is a primary muscle of the thumb. Its fibers are horizontal with a fan shape. Its origin is at the capitate carpal bone and bases of the metacarpals. Its insertion is at the medial side of the base of the thumb phalanx. Its location helps it do what its name indicates, adduct. When the fingers are flexing during this exercise, the thumb is active as it adducts. The adductor pollicis is a primary component of grip strength performance and overall hand functionality.

The lumbricals are a unique muscle in that they originate from the tendons of other muscles located in the hand. Each finger has its own lumbrical, except the thumb. Their origin is located at the lateral side of each tendon of the flexor digitorum profundus in the palm of the hand. Their insertion is located at the lateral edge of the extensor expansion on the first phalanx of each finger (except the thumb).

In between the metacarpals are the dorsal and palmar interossei. You can feel them when you locate the spaces between your metacarpals. These muscles attach at the sides of the metacarpals at their origin and insert into the extensor expansion of the phalanges. These intrinsic muscles of the hand, the lumbricals and interossei muscles, act to flex the fingers at the metacarpophalangeal joints as with the hand gripping motion.

Assisting with finger flexion and overall grip performance are the flexor pollicis longus, flexor pollicis brevis and flexor digiti minimi brevis. The flexor pollicis longus is the muscle responsible for flexing the thumb that originates at the forearm and inserts into the arm. The flexor pollicis brevis also manipulates flexion of the thumb and spans from the carpals and flexor retinaculum at the base of the thumb phalanx. The flexor digiti minimi brevis is a deep intrinsic muscle of the hand that flexes the “pinky” finger.

Two primary wrist extensors, extensor carpri radialis longus and extensor carpi radialis brevis act to stabilize the wrist during finger flexion.

Hand grip device, Plate-pinch grip.

Finger flexion improves grip strength, improving hand and forearm contribution to other exercises. Exercises that improve grip also complement the aesthetics of the forearms by increasing their size.

Finger flexion may be isolated to one hand with this machine (with a lighter weight to accommodate) or with individual hand gripping devices. This will allow the lifter to isolate the grip performance of both hands separately.

Grip training should be done at the end of an exercise session to not jeopardize the quality of exercise with fatigued grip when training larger muscle groups. It is ideal to perform this exercise on the same day of executing exercises that activate forearms. For example, after a back and biceps training session, finger flexion/grip exercises complement the activation of the forearms that has occurred during your back and biceps training.

Focus on the concentric portion of the contraction, concentrating on “squeezing” at the end of finger flexion as the rods are squeezed together.

Emphasis on eccentric contractions, prolonging the eccentric portion of the contraction, may also be incorporated in a training program focused on increasing strength. This should be implemented accordingly and with adequate muscle recovery as eccentric contractions cause substantial damage to muscle tissue.

Strategically varying your intensity (load) and volume (number of repetitions in a set) will optimize grip strength and forearm development with time.

Training grip and forearms before training larger muscle groups can decrease the quality of a lifting session if the grip and forearm muscles are fatigued initially. Many resistance exercises (e.g. biceps exercises) activate the hand and forearm muscles in the process to assist with larger muscles. This is why it is important to train them after training large muscles, at the end of a session.

Bouncing the weight at the end of the eccentric contraction before the concentric/squeezing phase can result in wrist and/or finger injury. Therefore, it is important to control the downward and upward phases of the exercise.

It is important that the lifter does not utilize momentum or strength from the upper body (e.g. arms, trapezius) to assist in the movement. This minimizes the potential of the muscles involved with grip performance. In addition, it is important to keep the wrists in a neutral position and not extend or flex wrists during finger flexion.

If proper technique is not adhered to (e.g. dropping the weight quickly instead of controlling the descent on the eccentric portion of the lift, lifting a load too heavy for the lifter), the likelihood of injury increases.

If proper recovery is not implemented between training days for optimal muscle repair of the intrinsic muscles of the hands and forearm muscles, the tendons become inflamed. Without proper rest and treatment, the inflammation remains and results in tendonitis.