Strain in Posterior Thigh Muscle (Hamstring Strain).

1. Hamstring Strain
Dr. Usha (PT)
Assistant Professor

2. Hamstring Muscle Strains
 Acute, moderate or severe
hamstring strains are common
injuries among sprinters,
hurdlers and long jumpers.
They also occur in other sports
involving sprinting, especially
football and field hockey.

3.  There is a tendency towards an increased incidence with increasing age.
Hamstring injuries occur frequently despite the prevalence of stretching
and strengthening programs.
Epidemiology
 Hamstring muscle injuries are a common injury in sports that involve
high-speed running and kicking.
 They are the most common and most prevalent injury in Australian
football, constituting 15% of all injuries, with the average professional
Australian Football League (AFL) club having six injuries per club (40
players) and 21 missed matches per club per season.

4.  Similarly, in British soccer, hamstring injuries make up 12% of
all injuries with an average of five per club per season,
resulting in 15 matches and 90 days missed. The average
injury caused the player to miss an average of 18 days and
three matches
 Hamstring muscle injuries have the highest recurrence rate of
all injuries with a recurrence rate of 34% in AFL football and
12% in British soccer.

5. Biomechanics of hamstring injury
 The majority of hamstring muscle injuries occur in the biceps
femoris muscle, mainly at the muscle–tendon junction. They
are usually a non-contact injury and mostly occur during
sprinting.
 During maximal sprinting the hamstrings become highly
active in the terminal swing phase as they work eccentrically
to decelerate the swinging tibia and control extension of the
knee.

6.  The hamstrings then remain active into the initial stance
phase, whereby they work concentrically as an extensor of the
hip joint.
 Recent studies have demonstrated that during unperturbed
sprinting the point of failure is most likely to occur during the
terminal swing phase just prior to foot strike. It is at this point
that the hamstrings are maximally activated and are
approaching peak length

7. Factors that predispose to hamstring strain
 Predisposing factors are generally divided into intrinsic (person-
related) and extrinsic (environment related) factors.
Intrinsic predisposing factors
Age
 Several studies have shown that increasing age is a risk factor for
hamstring muscle injury, even when the confounding factor of previous
injury is removed. Community level Australian footballers over 23 years
old were four times as likely to sustain a hamstring strain than those
younger than 23.

8.  This relationship may be related to decreased strength. This
may be due to an age related reduction in muscle fiber size
and number, leading to a loss of mass and strength. Thus age-
related denervation of muscle fibers may lead to increased
risk.
 It has also been suggested that it may be due to age-related
lumbar spinal degeneration, leading to L5 and S1 nerve
impingement, thus resulting in hamstring and calf muscle
fiber denervation, which then leads to decreased muscle
strength

9. Previous injury
 Previous hamstring injury is a major risk factor, but past
history of injury is associated with reduced strength so this
may be a confounder. Previous calf muscle, knee or groin
injuries have also been associated with an increased
likelihood of hamstring injury.
Race
 There is an increased incidence of hamstring injury in those of
black4 or Aboriginal8 ethnic origin.

10. Flexibility
 Prospective studies have shown either a significant
association between pre-season hamstring muscle tightness
and subsequent development of a hamstring muscle injury, or
a tendency towards a statistical relationship.
 Retrospective studies are of less value as any associated
muscle weakness may be the result, rather than the cause, of
the muscle injury. The retrospective studies have shown
mixed results

11.  A survey of stretching practices among professional football
teams in the United Kingdom found that more hamstring
strains occurred in those teams that did not stretch regularly
and/or hold their stretches for long periods.
 One study suggested that decreased quadriceps flexibility
(<52° knee flexion) had an increased risk of hamstring injury.

12. Strength
 Low hamstring strength has been shown in most studies to be a
significant predictor of hamstring muscle strain injury. However, this has
been contradicted by other studies. Retrospective studies have shown
that those with a history of hamstring injury have significantly weaker
hamstrings.
 It may be that the actual length at which peak torque in the muscle is
developed is most important rather than the magnitude of the peak
torque itself. Footballers with a history of hamstring strain develop peak
torque at angles representing shorter muscle length, which therefore
makes them vulnerable to load in the muscle under lengthened
situations

13. Neuromyofascial
 A number of authors have suggested a relationship between
increased neural tension and posterior thigh pain. The
presence of myofascial trigger points in the gluteal and
hamstring muscles appears to be associated with decreased
flexibility and possible increased motor fi ring of the muscle.

14. Lumbopelvic stability
 Neuromuscular control of the lumbopelvic region, including
anterior and posterior pelvic tilt, may be needed to create
optimal function of the hamstrings in sprinting and high-
speed skilled movement.
 Changes in pelvic position could lead to changes in length–
tension relationships or force–velocity relationships.
Improvements in lumbopelvic stability appear to assist in the
rehabilitation program.

15. Joint dysfunction
 As mentioned above, age-related lumbar spinal degeneration leading to
L5 and S1 nerve impingement may lead to hamstring and calf muscle
fiber denervation, which then leads to decreased muscle strength. An
increased incidence of lumbar lordosis was also noted in a group of
players who had a history of hamstring strain in the previous 12 months
when compared to an uninjured group.
 In those with hamstring strains the innominate bone at the sacroiliac
joint ipsilateral to the hamstring strain was found to be tilted anteriorly.
A bilateral anterior pelvic tilt has been associated with weakness of the
transversus abdominis, which may make the hamstrings functionally
tighter.

16. Extrinsic predisposing factors
Warm-up
 A physiological warm-up consisting of isometric contractions
increases the amount of force and length of stretch that the
muscle can absorb prior to tearing.
 There appears to be clinical evidence that muscle strain
injuries, in general, are more likely to occur without adequate
warm-up.

17. Fatigue
 Fatigued muscles are able to absorb less energy. Hamstring
injuries are more common at the end of matches and training
sessions in soccer, have a higher incidence in the fourth
quarter of Rugby union, and occur infrequently during warm-
up of the first quarter in Australian football.
 Fatigue may induce physiological changes within the muscle,
as well as altered coordination, technique or concentration,
predisposing the player to injury.

18.  The dual innervation of biceps femoris could lead to
asynchrony in the activation of separate parts of the muscle
and result in inefficiencies.
 Abnormalities in running style may be the consequence of
fatigue, increasing the workload of the stabilizing biarticular
muscles around the pelvis. When footballers become fatigued
during sprinting there is an earlier activation of the biceps
femoris and semitendinosus muscles.

19. Fitness level
 Inadequate pre-season training resulting in low fitness levels
may contribute to an increased hamstring injury rate.
Training modalities
 Too much emphasis on aerobic training instead of more high-
intensity running/acceleration drills has been suggested as a
causative factor. Abrupt increases in training volume and
intensity may also contribute to injury risk.

20. Additional specific predisposing factors in recurrent
hamstring injuries
 Inadequate rehabilitation: this may lead to deficits in strength
and/or flexibility.
 Angle of peak torque: as mentioned above, footballers with a
history of hamstring strain develop peak torque at angles
representing shorter muscle length, which therefore makes
them vulnerable to load in the muscle under lengthened
situations.
 Neural tension: injury may result in increases inneural tension

21. Prevention of hamstring muscle injuries
 Stretching- A warm-up stretching program was found to
statistically reduce the number of hamstring injuries in a
military population.
 Strengthening program- Correcting strength deficits can
lower injury to the hamstrings. Pre-season hamstring muscle
strengthening using an open chain weight machine reduced
the number of minor hamstring injuries but not the number
of significant injuries. Specific eccentric training may be more
important in view of the mechanism of injury.

22.  Thermal pants- The use of thermal pants has been suggested
to have a role in reducing the recurrence of hamstring
injuries.
 Combined programs- A number of multifactorial programs
appear to have been effective in reducing the number of
hamstring injuries. The programs have included:
 Increasing the amount of anaerobic interval rather than
aerobic training, stretching while muscle is fatigued, sport-
specific training drills, and closed chain rather than open
chain leg weights

23.  A program combining general interventions such as
improved warm-up, regular cool down, and a series of
exercises to improve stability of ankle and knee joints,
flexibility and strength of the trunk, hip and leg muscles, as
well as to improve coordination, reaction time and
endurance—this was found to be effective in reducing
injuries in soccer players, including thigh injuries
 A pre-season conditioning program consisting of sport-
specific cardiovascular conditioning, plyometric work, sport
cord drills, strength training and flexibility exercises in a
group of soccer players.

24. Clinical features
 The main aim of the clinical history, examination and
investigations is to differentiate between the significant
hamstring tear and neuromyofascial referred pain primarily
from gluteal trigger points but also from lumbar spine and SIJ
structures.

26. Imaging
 Ultrasound and MRI have both been found to be effective in
depicting hamstring injuries.
 Ultrasound may be the preferred imaging technique due to
lower costs, however, MRI is more sensitive for follow-up
imaging of healing injuries. The longitudinal extent of the
strain as measured on MRI is a strong predictor of the amount
of time needed until an athlete can return to competition

27. Management of hamstring strain
 There is very little scientific evidence on which to base one’s
management of hamstring injuries. Only one study has
compared the efficacy of two treatment regimens, so much of
the regimen described below is on the basis of our clinical
experience. Clearly, further research needs to be performed in
this area.

29. Acute management
 Acute injuries should always be assessed before any treatment,
including ice, is administered. The RICE program should be commenced.
Painfree, active knee extension may be performed while sitting following
10–15 minutes of ice.
 This active stretching of the hamstring is conducted for 5 minutes and
the whole process may be repeated every hour in the initial phase. The
athlete may actually wake every few hours to use this technique in order
to ensure inflammation settles as quickly as possible.
 This process normally takes place over two to three days or until
inflammation has settled.

30. 
Active pain-free knee
extension in the acute phase

31. Medication- The intended aim of using NSAIDs is to keep the
inflammatory process under control an d to provide analgesia.
Stretching- In the acute phase, pain-free range of motion
should be achieved as soon as possible. If there is long-term
loss of range of motion, then specific stretching should be
undertaken to focus on the affected area.

32. Hamstring stretches
(a) Hamstring stretch with contralateral knee flexion. The
lower leg can be placed in different degrees of external
and internal rotation to maximize the effectiveness of the
stretch
(b) Hamstring stretch with bent
knee results in maximal stretch
to the upper hamstrings

33.  Soft tissue therapy- At an appropriate time depending on the
severity of the injury, soft tissue techniques can be used in the
treatment of hamstring strains. The distal musculotendinous
region is palpated and treated in knee flexion with the foot
resting on the therapist’s shoulder.
 Digital ischemic pressure and sustained myofascial tension
are used. Abnormalities of the gluteal muscles may be
associated with hamstring strains. These regions may be
treated in a side-lying position using elbow ischemic pressure
with the tissue on stretch and the muscle contracting.

34. Soft tissue techniques in the
treatment of hamstring injuries
(a) Sustained compression
force to hamstring
(b) Sustained myofascial tension combined
with passive knee extension. The hand or the
elbow (illustrated) is kept stationary and the
release is performed by passively extending
the knee (arrow)

35. (c) Digital ischemic pressure to
the distal biceps femoris tendon
(d) Treatment of the gluteal region in a
side-lying position using elbow ischemic
pressure with the muscle contracting

36. Neural stretch
Stretching of neural structures should be performed as part of the
treatment of hamstring pain if tightness has been detected on neural
tension testing. These neural stretches may be performed with the aid of

37. Manual therapy
 The presence of a degree of hypomobility in any segment of the lumbar
spine, found on examination, should be treated. If increased neural
tension is found at examination, neural stretches should be included in
the treatment regimen.
Strengthening
 Strengthening is an essential component of prevention and
rehabilitation of hamstring injuries. Muscle strengthening should be
specific for deficits in motor recruitment, muscle bulk, type of
contraction (e.g. eccentric/concentric) and ability to develop tension at
speed.

38. Strengthening exercises
(a) Concentric and eccentric exercises—prone.
From a position of hip flexion, the knee is flexed (concentric) and/or extended
and stopped just prior to full extension (‘drop-and-catch’) (eccentric). Weights
can be added gradually and speed can be increased progressively

39. (b) Nordic eccentric hamstring exercise—patients allow themselves to fall
forward and then resist the fall for as long as possible using their hamstrings

40. Irritable Hip
 ‘Irritable hip’ is common in children but should be a diagnosis
of exclusion. The child presents with a limp and pain that may
not be well localized.
 Examination reveals painful restriction of motion of the hip
joint, particularly in extension and/or abduction in flexion.
 In the majority of cases, a specific cause is never identified
and the pain settles after a period of bed rest and observation.
Radiographs, bone scanning and blood tests are usually
normal, and the child is treated with rest.

41. Thank you