Biceps Femoris

Structure:

This course describes the anatomy and integrated function of the biceps femoris muscle group (a.k.a. the hamstrings, lateral hamstrings, leg biceps, posterior thigh muscles, etc.). This muscle includes two heads, the long head crosses the hip and knee, and the short head crosses only the knee. Both heads are located within the posterior fascial compartment of the thigh, between the lateral and medial intermuscular septa, abutting the lateral intermuscular septum. Research suggests the biceps femoris only accounts for about 3.9% of the total muscle mass of the thigh and is composed of primarily type I muscle fibers.

Function

Both heads perform similar functions at the knee joint, but only the long head crosses the hip joint. Both heads of the biceps femoris are considered the prime mover during knee flexion and tibial external rotation, and the long head of the biceps femoris is a synergist during hip extension and hip external rotation. This course also describes the role of the biceps femoris on knee joint, hip joint, and sacroiliac joint (SIJ) arthrokinematics, fascial integration (sacrotuberous ligament), subsystem integration, and postural dysfunction. For example, the long head of the biceps femoris is part of the deep longitudinal subsystem (DLS) , which may increase tension in the sacrotuberous ligament, increasing the stiffness of the SIJ (restricting nutation). If the biceps femoris and DLS are over-active, this could excessively increase SIJ stiffness, contributing to an asymmetrical weight shift during an overhead squat assessment , and postural dysfunction (e.g. movement impairment) of the lumbopelvic hip complex and/or lower extremity .

Practical Application:

Sports medicine professionals (personal trainers, fitness instructors, physical therapists, massage therapists, chiropractors, occupational therapists, athletic trainers, etc.) must be aware of the integrated function of the biceps femoris for the detailed analysis of human movement, and the development of sophisticated exercise programs and therapeutic (rehabilitation) interventions. For example, altered activity and length of the biceps femoris may contribute to hip pain, hamstring injury, hamstring muscle strain, hip joint impingement, low back pain, knee valgus, knee varus, and knee pain. Altered biceps femoris activity may also result in a relative reduction in gluteus maximus and gluteus medius activity, resulting in a significant decrease in lower body speed, agility, and strength, and a reduction in the effectiveness of resistance training routines intended to improve lower body strength and hypertrophy (bodybuilding). Deeper knowledge of biceps femoris anatomy is essential for optimal assessment, intervention selection, and building a repertoire of biceps femoris-specific techniques.

Case Study: Sacroiliac Joint Dysfunction

Assessment

• Client/Patient History: Low Back and Sacroiliac Joint Pain
• Overhead Squat Assessment:
  • Asymmetrical Weight Shift Left (no improvement with Heel Rise Modification)
• Goniometry:
  • Hip Internal Rotation in Supine : Right = 25°, Left = 40°
  • Hip External Rotation in Supine : Right = 30°, Left = 50°
• Manual  Muscle  Testing:
  • Gluteus Medius : With compensation
  • Gluteus Maximus : With compensation (lumbar extension)

Sample Self-administered Intervention

• Release
  • Right Biceps Femoris Self-administered Static Release
  • Right Piriformis Self-administered Static Release
  • Right Adductor Magnus Self-administered Dynamic Release
• Mobilization or Manipulation
  • Right-side Down Open Books
• Lengthening
  • Adductor Mangus Static Stretch
  • Active Biceps Femoris Stretch
• Activation
  • Left Gluteus Maximus Activation
  • Left Gluteus Medius Activation
• Integration
  • Single-leg Touchdown with Posterior Pull

Sample Manual Therapy Intervention

• Manual Release
  • Right Biceps Femoris Static Manual Release
  • Right Piriformis Static Manual Release
  • Right Adductor Magnus Static Manual Release
• Mobilization or Manipulation
  • Right SIJ Mobilization
• Manual Lengthening
  • Rigth Manual Adductor Magnus Stretch
• Activation
  • Left Quick Glute Activation Circuit
• Integration
  • Single-leg Touchdown with Posterior Pull

Brookbush Institute’s most recommended techniques for the Biceps Femoris (see videos below):

• Self-administered Release: Biceps Femoris Foam Rolling
• Dynamic Release: Biceps Femoris Self-administered Pin and Stretch
• Manual Release: Static Manual Release of the Biceps Femoris
• Vibration Release: Hamstring Vibration Release
• Active Stretch: Biceps Femoris Active Stretch
• Dynamic Stretch: Biceps Femoris Dynamic Stretch
• Subsystem Integration: Single-leg Touchdown to Scaption

Caption: The biceps femoris muscle running on the posterior side of the leg