Post on 22-Jan-2018
"The role of the isokinetic test in ACL Rehabilitation for Athletes"
Alessandro Giannini
Porto 19 October 2017
1. Isokinetic test: merits and limitations
2. How to perform an isokinetic test of the knee
3. How to use the isokinetic test in ACL rehabilitation
History….
At the beginning of 900 the scientists asked for a very «simply» thing:
So starts a journey that is not…
Ended jet…..
measure human force.
Force as a variable
“The heat of shortening and the dynamic constants of muscle.”
1938
Archibald Hill
A «simply» solution
....keep a variable constant
In 1967 J Perrine introduced a new speed controlled device which was described as 'cybernetic exercise'.
His first machine was called the Cybex 1
Force (toque) change even at constant speed
Different type of effort
Inertia is the resistance of any physical object to any change in its state of motion.
This includes changes to the object's speed, direction, or state of rest.
But can we control muscle force consciously?
What does Maximal Volountary Contraction (MVC) really mean?
Trought burst superimposition we can increasemuscle force up to 20%
You can not really use this 20%?
Funny facts relative to muscle control
the recruitment patterns of different types of motor unit are
related to the mechanical requirements of the locomotor task.
In facts …… More than reflex…..
Motor redundancy
Motor movement and muscles contraction are organized based on the
The purpose is to reduce noise of task relevant variable
intention of the action
A briefly stop….
• Muscles have intrinsic property well describedby force-velocity relationship
• Each type of movement (isometric, isokinetic,isotonic, ballistic, ecc…) is unique and imposedifferent demands on muscles• Force measured in different situations are
related one another but are not the samething
• Spinal reflexes are very relevant to determinemuscle activity and final force profile
• Muscle are recruited and coordinated basedon movement intention
Key Points:
Which part have the Isokinetic test in ACL rehab?
Stregth really matter?
How do we test strength?
Keep things simple
Test:
• 5 repetition• Concentric knee extension and
flexion• At 60°/s• Using gravity correction• Use full range of motion• Measuring peak torque and H/Q
We have told more about that in the workshop:
Result:
• Less than 10% difference in peak torque• H/Q ratio more than 60
When to test it
• Extension as the controlateral knee• Minimal or no swelling• Good gait coordination• Minimal pain during walking (NRS 2-3)• Active flexion more than 120°
As early as possible but…. Isokinetic test is safe….
…and reliable ….
With Biodex IC is around 0,96-0,98 if well executed
Czaplicki et al. 2015
Up to six months?
On regular based on deficit until we achive <10% of deficit
• Strength deficit (and kinematic alterations) more then 15% may still occur a year or longer after a reconstruction
• The deficits are due to• Muscle atrophy• Neural inhibition that prevents the quadriceps from being fully activate
• Arthrogenic mucle inhibition (AMI)
Lewek et al. 2002
What is AMI
How may we fight AMI?
3 to 5 days after surgery
Stokes et al. 1994
30 minute of cryotherapy BEFORE exercise
Reduce AMI (for 20 minute) and increase peak torque
Rice et al. 2009
HF TENS on the knee
120-150 Hz, pulse width, 0.1-0.15 sec
Pietrosimeone et al. 2009
Aspiration Cryotherapy
How may we fight AMI?Neuromuscular electrical stimulation
During isometric contraction, 60°-90° kneeflexion, at least 50% of MVIC
Delitto et al. 1988
Mental Training
15 min/day, 3 sets of 10 imagined maximal knee
isometric extensions
Lebon et al. 2012
Start 7 days post-op, 20 min per day, 80% 1RM, 5×6 reps (2 min recovery),
conc-eccentric
Controlateral Training
Papandreu et al. 2012
How to plan a correct strength program?
If you are not able to design a
performance training program for an
athlete pre-injury, how are you able
to effectively design a performance
training program to return to
competition after an injury?
Bill Knowles
How to plan a correct strength program?
1. We need an adequate stimulus to “overwhelm” or “embarrass” the body a little so that it adapts slightly• Our body can’t adapts too much and the stimulus
has to be hard to complete but not devastating
2. After a stimulus we need adequate rest
3. The body will adapt very specifically to the type of training that we are doing
All type of training is based on three very simple concepts
Steve Magness
How may we fight AMI?
1 RM Strenght trainingVelocity training
We need both type of training in a progression way
We need to move from «general» to «specific»
What “specific” is depends of athletes in front of us
This can be applied to any “level” of description
Which type of exercise we need?
• Isokinetic? • Eccentric? • Concentric? • Isoinertial?
But we have concluded that muscle is activated based on intention of movement rather than the precise type of muscular contraction involved…….
Take home message
• With Isokinetic test we can make an «educated guess» of how much strengthdeficit we have
• Reducing force deficit is an important part of rehabilitation but is not everything
• Control AMI• Work from general to specific even to
increase muscle force• Isokinetic training play a rule but do not use
just that one
How may we fight AMI?