Effects Of Post Activation Potentiation On Isometric Strength: Pilot Study Reflection Report

Methods

The effect of post activation potentition on isometric strength in patients with anterior cruciate ligament injury post rehabilitation pilot study is the study that is being done to test the effects and improvement of the patient’s ligament muscular performance after the stimulation through a series of exercise (Sands 2008).

In this process there are various methods of stimulation that are used which can be isometric or even the dynamic contractions which involves the entire body vibrations (Hodgson 2015).

These methods however lead to power outputs which are mainly augmented in other activities which include the explosive contractions and sports specific action.

However the exercise will also lead to increase in maximum production of forces and the power of the muscles (Sale 2014).

In this case research there are three theories to be proved that tends to explain the physiology mechanism of the post activation potentition ,the first states that prior to stimulations phosphorylate myosin regulatory light chain move them from the myosin thick body while bringing them close to acting filaments in order to increase the muscular sensitivity and eventually increase the sarcomeric apparatus interaction (Judge 2009).

The second theory states that the preconditioning activities helps in the increment of transmittance of the excitations potential on the synaptic junctions and the spinal cord level, however this is achieved through the continuous study to do assessment of the electro-myographic data on the muscles which is potentiated (Rixon 2011).

In the third theorem the theory state that reducing of the potentation angle that can be caused by the potentiating stimulus (Vandenboom 2012), might end up increasing the power and strength when the change allows direct transmissions from the muscles-fiber force to the tendons (Sweeney 2013).

Therefore through this study there will enough evidence that will be used to prove the three theories true where there will be the use of various stimulation variables to be used (Vandenboom 2015).

In the pilot study there will be use of the stimulations and the assessments values will be read and recorded  where  they will vary due to difference in the intensity and stimulus type, however there will be set interval between the stimulus and the assessments and this interval should be having long interval in order to allow the participants to recover from any form of fatigue (Rassier 2012), however the interval is also somehow short  to allow the assessment of the muscles in the potentiated state that takes about 20 minutes after the stimulations (Macdougall 2014).

Participants

In this pilot study the there will be stimulations and assessments intervals of 5 to 20 minutes ,however the neuromuscular factors which includes the strengths level (Mclean 2016), fiber types distributions ,training levels and the power/strengths ratios are very essential in performance of the individuals responsiveness to the post activation potentition (Gordon 2011).

In this study the most important aspect is the strength productions and this is because it is used in the investigating the neuromuscular system (Vandenboom 2015), however the isometric voluntary contractions are therefore used in this assessment of the muscular strengths where various variables are obtained which includes:

1. The  isometric peak torque (IPT)
2. Contractile  impulse (CI)
3. Rate  of torque development (RTD)

However the strengths assessments protocol will be done using a given number of MVC where a there will be a fixed rest interval of four weeks where the contractions with greatest isometric peaks torques will be used to do the analysis (Abrantes 2010).

Therefore this pilot study since it is using the isometric strength assessment protocols the study will adopt the use of the potentiating protocol where 3 to 5 seconds contraction under an interval of 30 minutes is used (Harrison 2010).

Therefore the main aim of our study is comparison of the similarities of the PAP stimulation and strength assessment protocols.

In this pilot study there was involvement of two participants who were in  of 20 and  50 years respectively  and they were the patients admitted for the rehabilitation due to the anterior cruciate ligament  injuries on their legs ,these participants were voluntary being involved in the study.

The study was designed to take a period of four weeks and every week the participant were to participate for only three days but for at least four activities in those each days.

The criteria used were to ensure that the participants were not in any physical activities for the past five months and they had no injuries on their legs especially on their knees joints.

However those volunteered they were not supposed to participate in extra physical activities apart from the routine activities given in the entire study period (Santos 2008).

The volunteers were given the guidelines that they should follow for the entire study period and they had to read their rights and the possible risks and they signed the consent terms of the research body.

During the study the volunteers had to have a visit in the laboratory room thrice in a week every for four weeks, however before the start of the tests the participants will be done orientation of what the study was all about and the type and number of activities they were to be involved in during the pre-activation and post-activation strengths tests.

Experiment Designs

However in this orientation session the volunteers had to undertake non-specific five minutes run at a speed of 5km/h and then they perform some specific warm up exercises which includes three sub-maximal isometric contractions prior the performance of the MVC knees extensors using the dynamometer but in this there were no readings that were captured (Hopper 2013).

In the pre-intervention  visits the  experimentation  sessions was also done where the volunteers performed the previous warm up exercise and then they performed six mvcs for the knees extensors inside the isokinetic dynamometer, in this case three readings were taken from each participant and then their average were to be recorded in the table 1 below.

	PARTICIPANT 1	PARTICIPANT 2	AVERAGE
DAY1 READINGS
DAY2 READINGS
DAY 3 READINGS
		AVERALL AVERAGE

Table 1: Pre –Intervention Reading

Finally In the post-intervention  visits the  experimentation  sessions was also done where the volunteers performed the warm up exercises and then they performed six mvcs for the knees extensors inside the isokinetic dynamometer, where also in this case other three readings were taken from each participant and then their average were to be  recorded as shown in the table 2 below.

	PARTICIPANT 1	PARTICIPANT 2	AVERAGE
DAY1 READINGS
DAY2 READINGS
DAY 3 READINGS
TOTAL		AVERALL AVERAGE

Table 2: Post –Intervention Reading

However the overall average readings of the two sessions in the pre and post intervention sessions were to be recorded in the table 3 below.

	PRE-INTERVENTION READINGS	POST-INTERVENTION READING
AVERAGE READINGS

Table 3: The average Post –Intervention and Pre –Intervention Readings.

There was T seat set-up recording in the pre-intervention  sessions was also used in the other post-intervention  sessions. However the patients who were volunteers were given instructions to ensure they have enough rest and fully hydrated and alive on time to the laboratory during the testing period.

The patients however they were authorized not to engage in the activities that strains them in each day before the testing, however the tests were then performed in a controlled conditions where the room temperature was to be between 20⁰-23⁰ C and within same period interval not varying with more than 2 hours in order to minimize the variation in the results.

In the initial familiarization session all of the volunteers were given instructions and oriented to the procedures used in the test process using the dynamometer to eliminate chances of underestimating the muscle strength, however the volunteers a prior tests by undergoing some warm up for a 5 min session at 5km/h and then the warm up is followed by the three sub-maximal isometrics contraction of the knees extensor (Babault 2015).

The participants were then given the instructions to perform contractions as fast as possible using maximum force and they are involved in performance of MVC within five seconds.   

Pre-Intervention Reading

In this study the dynamometer and the excel computer software are used in the MVC measurement, however all patients during the testing process were sited upright on tests chair.

However the movements on the patient’s upper body were minimized using two crossovers shoulders harnesses and the belts on the abdomen where the thighs angle was to be at 86⁰.

However in this exercise the dynamometer axis was position along the right leg knee flexions-extensions axis while the lever’s arm was then attached to shanks using the straps.

Then the patients are required to place their legs in a relaxed form in order to allow the determination of gravitational effects on the limb and the lever’s arm to be carried out and be recorded.

Then there was performance of the MVCs on the knees extensors where a 75⁰ static knee joint angles which was full extension test (Allen 2008).

However the other maximal isometrics attempts were carried out  where each was done under interval of 3 minutes in order to allow the recovering intracellulars phosphocreatine reserve.

Then the patients were given instructions to extend the knees quickly and with maximum force possible where the MVC was done for approximately five seconds.

In this stage of study the torque contractions data was captured using 1000 HZ frequencies using the biological acquisitions modules which was synchronized using the isokinetic dynamometers.

However the resultant data filtration and analysis was done using the excel application to eliminate low pass values.

However the isometric peak torque (IPT) was the greatest value in the torque-time curve, and the time is recorded when the peak happened.

There is  the calculation of the contractile impulse using the torque time curves through the trapezoidal integration (Aagaard 2015).

However the Rate of torque development (RTD) was also gotten from the isometrics contractions torque’s time curve against time interval 0–30, 0–50, 0–100, 0–150, 0–200, and 0–250 ms relative to the onset of contractions.

However the was the calculation of the Maximal rates of torques developments (RTD_MAX) which was obtained from the most steep point on the torques-tine curves.

Therefore on-set of muscles contractions was the time points where the knees extensor torques exceeded the baselines by 2.5 % of the baseline’s to peak differences.

Finally the EMG data analyses were carried out using the ms excel software where there was filtering of both high and low pass done.

The values of average root mean square (RMS) of EMG signals was then obtained using 0.5 seconds intervals while conducting the MVC ,however the EMG was obtained as percentages of the various(%RMS_MAX) in the first experimental contractions (Mahlfeld 2014).

Post-Intervention Reading

The data corrected in the pilot study was recorded and expressed in form of average of three readings on each patients in the both pre-intervention and post-intervention session,the data normalization was done using the p- test .However there was use of one way ANOVA measurement that was used to compare values obtained in the pre-intervention sessions in order to understand the familiarizations and the learning effects.

However the difference in measuring criterions which included IPT, tIPT, CI, and RTD and they were generated while conducting the experiments.

Finally relationship of the various changes in the 1^st MVC in the pre-intervention session, and  2^nd  MVC in the post-intervention session their dependent variables assessments were carried out using the Pearson’s product moment correlation coefficients where the significant level was p < 0.05.

During the test processes the various results of the MVC1 in the pre-intervention session, MVC2  in the post intervention session  were corrected depending on the day of the week ,however there were two participants in this case and the weekly average reading scores were used to get the MVCs score as shown in the tables below.

Table 4: Values of Pre –Intervention Readings.

	Participant 1	Participant 2	Average
Day1 Readings	50	48	49
Day2 Readings	60	68	64
Day 3 Readings	78	91	84.5
		Averall Average	65.83

Table 5: Values of Post –Intervention Readings.

	Participant 1	Participant 2	Average
Day1 Readings	60	55	57.5
Day2 Readings	65	67	66
Day 3 Readings	81	90	85.5
Total		Averall Average	69.66

Table 6: Values of Averages of the Pre –Intervention Readings and Post –Intervention Readings.

	Pre-Intervention Readings	Post-Intervention Reading
Average Readings	65.83	69.66

Figure 1: Pre-intervention graph.The average reading isometric peak torque values from the average of three readings from the two patients in the pre-intervention session. MVC1: The pre-intervention experiment maximal voluntary isometric contraction.

Figure 2: Post-intervention graph.The average reading isometric peak torque values from the average of three readings from the two patients in the post-intervention session. MVC2: The post-intervention experiment maximal voluntary isometric contraction.

 (miyamoto 2011).

Figure 3: Post-intervention and pre-intervention graph.The average reading isometric peak torque values from the average of three readings from the two patients in the pre-intervention session and the post-intervention session. MVC1: The pre-intervention experiment maximal voluntary isometric Contraction; MVC2: The post-intervention experiment maximal voluntary isometric contraction.

During the test the values of the tests were recorded and used to perform analysis, however from the analysis it had been identified that the IPT values for the pre-intervention session and other post-intervention sessions had great significant difference where the pre-intervention session had 65.83 while the post-intervention session had 69.66 and thus there was effects in strength assessments in the tests conducted (Maganaris 2014).

Therefore as the patients continued with the exercises their muscles tended to be more and stronger and therefore there are positive effects of post activation potentiation on isometric strength in patients with anterior cruciate ligament injuries in their post rehabilitation process.

The Average Post-Intervention and Pre-Intervention Readings

This study was aimed to conduct the PAP investigation on it effect on the isometric strength assessment performed with two MVCS where each MVC was having an interval of three minutes of resting between the tests, however in this study there were no effects of learning that were identified in the pre-intervention session this is because the IPT values in the pre-intervention session and the post-intervention session  had slight noticeable significant differences (RYDER 2013).

However there was some significance difference in the IPT, TIPT, RMS and RTD in the two pre-intervention and post-intervention MVCs experiments, which eventually indicates the PAP that was used either increased or decreased in terms of in strengths related criterions measures.

However the familiarization session is vital methodology in the studies used to do the investigation of the isometrics and dynamics muscular strengths, however the familiarization session is used to prevent the over or the underestimating the strengths assessments (Sasaki 2012).

The PAP on the other side is important where it mainly play a significant role in enhancement of muscle powers that is assessed by use of the isokinetic contraction, jump and some other exercise activities .

Conclusion.

Through this study I conclude that the PAP has much effect on on isometric strength in patients with anterior cruciate ligament injuries during the rehabilitation process, therefore I can recommend the exercising of the injured patients which will as a result lead to strong muscles development (XENOFONDOS 2015).

In this study there were various aspects that were considered and these were important to enable the conduction of research and getting possible results of the effects of exercise by the patients ,some of the aspects considered was the determination of participants, familiarizing process ,data processing ,data analysis and the results evaluation.

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