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Case Series
New insights to ACL-/PCL-rehabilitation
for professional football players
Myontec’s wearable EMG-technology utilization
in postoperative rehabilitation
Jari Puustinen - Sports Physiotherapist
Naprapath D.N. - Student of Sports Medicine, University of Eastern Finland
Introduction
According to the Federation of International Football Association
(FIFA) Soccer is the most popular sport worldwide with 265 million
players. Among them are 38 million licensed players, of which 10 %
are women (statistics from 2006).
Up to one fifth of football-injuries involve the knee joint. The most
common knee injury is the Anterior Cruciate Ligament (ACL)-tear that
significantly affects a player´s career, with both short- and long-term
consequences. A more uncommon injury is the tear of the Posterior
Crucial Ligament (PCL), which compared to ACL-tears are less
frequently operated.
‘The most common injury is the Anterior
Cruciate Ligament (ACL)-tear that significantly
affects a player’s career,
with short- and long-term consequences.’
The present study investigated players´ rehabilitation-process results
and the EMG-wearable technology`s usability and value in assessing
the state of functional recovery applied for ACL-/PCL-operated football
players during the rehabilitation. Myontec`s Mbody Shorts are the
world’s first EMG-based muscle sensing smart Shorts.
This study looked for similarities between information from EMG
measurements and results from clinical measurements. It also aimed
at identifying new tools to evaluate knee- and muscle-performance
during rehabilitation and late stage reconditioning.

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Methods and tests
The study-group consisted of four male, adult professional football-players, whom had ACL- or PCL-recon-
struction. All 4 players followed a sport-specific rehabilitation protocol for soccer. In the study rehabilitation
policy followed criterion based rehabilitation practice guidelines, Soreness rules, Return to sport criteria
(Adams et al. 2012, Della Villa et al. 2012), the so called traffic light concept (as described by Tsapralis
2014), Rehabilitation program succession of 5 phases (each characterised by the achievement of clinical and
functional goals, Tencone 2012) and progression in running.
3 months after their reconstructive-operation of ACL / PCL, Players performed a battery of tests every 4 weeks
(test, which were tolerated at that time). Tests were made to assess their progress and / or deficits in order to
further program their rehabilitation processes. These tests consisted of:
• Measurement of range of motion (ROM)
• Test for muscle atrophy (thigh circum. 5/10 cm above the patella)
• Isometric muscle strength-test of m. quadriceps and m. hamstring
• 1 hop test (1 hop) and Triple hop test (3 hop)
• Yo-Yo Intermittent Recovery Test Levels 1 & 2 (YoYo IRTL1 & 2)
• Knee injury- and Osteoarthritis Outcome Score (KOOS); Muscle activation and –function in daily living
(ADL) and Sports and recreational activities (SPORT)
Myontec`s Mbody Shorts were used to evaluate the athlete´s performance capacity in:
• Strength tests
• Leg press endurance-test (from 90 degree angle against 30 kg resistance, 2 x 25 repetitions on each leg,
no resting time between sets, with submaximal load)
• Drop jump test (bench 30 cm, drop to the floor, jump with 2 legs as high as possible and smooth landing
to the floor)
• Yo-Yo Intermittent Recovery Test (YoYo IRTL 1 & 2)
• Treadmill-running test (at 1 degree inclination 3 minutes steps, 2 km/h increase of the level starting from
5 km/h and ending to 13 km/h speed)
Results
Every player / participant reached all the Return-to-sport criterias 4-8 months after his ACL- / PCL-operation.
All the players reached the criteria as set by the studies.
Return-to-sport criteria*
Minimum 12 wk postoperative 90% or greater on KOS-ADL
90% or greater on quadriceps index 90% or greater on global rating score of knee function
90% or greater on all hop tests
Abbreviation: KOS-ADL, Knee Outcome Survey-activities of daily living.
*All criteria must be met prior to beginning a return-to-sport progression.
Table 1. Return to sport criteria (Adams et al. 2012).

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All injured players returned to play at the same level as before the injury. The average time to return to full
training after reconstruction was 150 - 240 days.
‘Real-time muscle-group specific information enables us to assess
the symmetry, relaxation and progression during exercise.’
Measurements with Myontec`s Mbody Shorts
highlighted asymmetries between the player´s right and
left Hamstring muscle-activations, especially during the
Treadmill-tests. Detecting this asymmetry in an early
stage of rehabilitation gave possibility to highlight and
focus on the rehabilitation content more accurately.
Monitoring of this asymmetry substantially helped to
reach muscle balance in the activation of the Hamstring
muscles during the rehabilitation process (Figure 1).
Figure 1. Case 1 player, findings of asymmetry and reconstitution in Treadmill-tests.
In the Yo Yo-intermittent Recovery Test and running tests (Treadmill-test) were detected graft-hamstring-
muscles activation-relaxation-deviations in the Mbody EMG-data for some players (Figure 2). These deviations
did not emerge in the power-levels between the legs or in the Hops results.
Treadmill 5km/h - Muscle Balance %
Treadmill 9km/h - Muscle Balance %
Treadmill 11km/h - Muscle Balance % Treadmill 13km/h - Muscle Balance %
Treadmill 7km/h - Muscle Balance %

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Conclusions & actions: Treadmill running-test
In Case 1 the training-method was changed 5 months after the
operation to power training (force-velocity).
The decision was made based on EMG-data and strength-
measurement -results. EMG-data indicated the difference between
muscles firing and -relaxation ability on right and left hamstring-
muscles.
6 months after the operation strength-levels between right and left
hamstring-muscles were identical. Subject was able to finish the
season without further symptoms.
Total activation level could give misleading information if used
straightly. There is a need to check activation-relaxation-deviations
of the muscles.
Figure 2. In case 1 the rehabilitation / training-protocol was changed more towards speed/power training after 5 months of training.
From the EMG-data was detected, that the Hamstring-muscle´s innervation did not work similarly in both legs.
Figure 3. Mbody EMG-data results show improved muscle-activation-balance in Leg press during rehabilitation.
Case 1 leg press balance % Case 2 leg press balance %
Case 3 leg press balance % Case 4 leg press balance %

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Discussion
ACL-injuries for soccer players are commonly treated surgically and clinical results, with return-to-play at
the same elite level, can be expected. This study aimed to find similarities between EMG-results compared
to results, what we got from the clinical measurements. On the other hand the aim was to find new tools to
evaluate knee- and muscle performance during rehabilitation and late stage reconditioning. This study was
more to find similar phenomenon and insights to evaluate the rehabilitation process, that we got from the other
measurements and to compare the usefulness of EMG smart shorts in a rehabilitation process.
‘Opportunity to assess muscle-functions
and fatigue during running,
which is crucial information for footballers.’
Conclusions
Functional multi-testing offers a wide variety of information. Criterion based rehabilitation ensures the player`s
safety and a controlled process to return to sport.
From this study´s point of view Wearable EMG-technology gives:
• A whole new perspective on knee postoperative rehabilitation and to assess a functional and sports specific
performance where the focus should be on the late stage rehabilitation
• An opportunity to assess footballer´s muscle-function and fatigue on running which is crucial information
for footballers
• Real-time muscle-group -specific information to assess the symmetry, relaxation and progression in
function
• Potential new tool to evaluate different tasks during the rehabilitation
• Information to plan individual progression during the rehabilitation to achieve better performance and
symmetry between the legs
• New insight to evaluate the hamstring imbalances and fatigue during and after running
EMG provides us with a lot of new information for which we will need further investigations and validations to
benefit from the full potential.
A lot of work still needs to be done, and will be done, to help therapists, coaches and athletes to read and
analyze all the data provided by Myontec’s Mbody EMG-Shorts. However, we are convinced of the positive
impact and added value through this technology during the rehabilitation and late stage reconditioning and
monitoring process.