Muscle Monday – Bicep Femoris
Origin and Insertion: 
Starting on the 3rd sacral dorsal spines, it continues on the 4th & 5th and 1st caudal vertebrae; gluteal & coccygeal fascia, the sacro-iliac and sacro-tuberous ligaments. A secondary primary origin arises from the ischiatic tuberosity via strong tendon.
Inserting to the patella, lateral patellar ligament, femur, tibia crest, fascia latae and calcaneus. The bicep femoris is maintained in this position behind the femur by a strong band of fibrous connective tissue that holds an attachment to the upper and posterior part of the femur.
Shape: Penniform. Long thick and fleshy, narrow from the dorsal origin becoming wider then splitting into 3 segments.
Action: This is a multi-functioning muscle; extension and abduction of the limb, extend the hip and flex stifle. Also assists in extending the hock and flexing the stifle joint. Acting with other complimentary muscles on the opposing side, it assists to support and balance the body during the action of rearing.
Nerve Supply: Caudal gluteals, ischiatic and fibular
Problems: Issues with this muscle can be viewed as scuffing of the hind leg and a shortening of forward impulsion & movement. The horse may exhibit difficulty in engaging the hind end for collection and other similar movements, like that are required in the high-level dressage, jumping or working on inclines. Horse with bicep femoris dysfunction may hold his leg flexed or tucked under the hind, exhibit a shortened hock extension, toe scuffing and shortened protraction.
Comments: Caudal femoral muscle that works with the semitendinosus to work as supportive flexors of the stifle and act as antagonists against the quadriceps femoris.
The bicep femoris is one muscle that makes up the ‘hamstring’ group of muscles, of which there are two more; the semitendinousus and semimembranosus, the bicep femoris is the more powerful of the group.
The bicep femoris are important for patella function, the movement is to help pull the patella to the side and releasing it from the trochlea.
Human equivalent comparison: Symptoms include tenderness and swelling where the tendon inserts into the bone. With biceps femoris tendinopathy the tender area is to the outside back of the knee. If the other two tendons are involved there may be tenderness medially. There may be pain when trying to bend the knee against resistance as well as stiffness after exercise and the next day. The athlete will often have tight hamstring muscles.
Associated Riding Discipline Concerns:
Hunters: Irish Draft and thoroughbreds and their associated cross, Warmbloods and crosses can have issues with this muscle from traversing uneven terrain, leg stresses and jumping and landing, but particularly during the take off phase of the jump due to the forces of propulsion.
Jumpers ( can be thoroughbred, warmblood predominantly, quarterhorse and cross breeds) suffer during the take off stage to the flexor and extensor muscles. Footing, slipping, too hard or too soft ground can contribute and stretching beyond normal range of motion.
Dressage horse (warmbloods and crosses, appaloosa, arabian and cross, thoroughbreds, quarterhorses) have a huge demand for precision, elegance and finesse as well as enormous co-ordination of execution of the high level movements. Stresses occur predominantly to the hindquarters, back, hip, stifles and hocks and lower limbs due to the pivoting and carriage.
Eventing (thoroughbreds, trakehners, warmbloods and crosses) horses need to be hugely versatile and requires fitness, stamina and speed and precision and athletic ability for the jumps phase of the dressage, area jumping and cross country work out of a three day event with many individual and group muscles taking the strain of the multi-discipline workout. Inflammation and contracture (shortening and hardening of the muscle).
Polo (Polo and Polocrosse) have smaller horses (ponies, smaller thoroughbreds, quarterhorses) preferred for their quick speed and agility to turn, rein backs and sliding stops. The lower limbs, ligaments and tendons are at serious risk and constant pressure for catastophe. Hind quarter muscles play an important role in propulsion and acceleration and are particularly stressed.
Racing is now popular with the thoroughbred, quarter horse and also the Arabian. The very nature of the strain placed on the horses body for speed and stamina can have overall influence on the body however perhaps the more commonly muscles effected could be in the neck, chest, back and hindquarter region. Inflammation present in over-taxed muscles as well as lactic acid, strains, tears and lower limbs catastrophes such as tendons bow, ruptures and strains common.
Steeplechaser and jumps horses are run at speeds over several hundred meters to kilometers whilst also needing to navigate obstacles during the course of the race. Most stresses are built up the back, and are very similar muscular to that of the flat racer coupled with the impact stresses seen in the jumper. Most or all muscle groups can or will be effected with additional inflammation and toxin build up as a result of the work performed.
Harness racing, trotting and pacing are predominantly standardbreds and thoroughbred horses that are raced on an oval shaped (think of the camber for the limbs and muscles) track pulling a 2 wheeled sulky at speed. The trotters gate is NSF:OSH and OSF:NSH coupled movements with pacers their gate is NSF:NSH and OSF:OSH together. Typically there will be hindend issues, neck and shoulders and jaw from the placement in harness, as well as overall stress and strain. Trotters are generally faster than the pacer, but pacer may exhibit more fatigue due to the dynamic nature of the biomechanics required to pace at speed.
Melissa Longhurst is a certified Equine Body Worker (EEBW) and Equi-Tape Therapist working in the
Mackay & Whitsunday’s region of Queensland.
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Equine Massage should not be used as a substitute for veterinary care. If in doubt of your horses’ health or well being, Melissa will refer you to your preferred veterinarian prior to commencing any bodywork. Horses under the care of a veterinarian should first be cleared by the attending veterinarian to ensure that massage is appropriate for the horse at this time.