Learn.Physio

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ISSUE 3, NOVEMBER 2020

THE
LEARN.PHYSIO
JOURNAL CLUB

BY MICK HUGHES
APA TITLED SPORTS & EXERCISE PHYSIOTHERAPIST

Welcome to another edition of the Learn.Physio Journal Club!

Welcome to issue #3 of my research reviews and thanks once again for your interest in keeping up to date in the sports physiotherapy world. If you’re new to The Learn.Physio Journal Club and missed the first 2 issues, you can catch up by clicking here.

In this issue I review 2 distinctly different papers looking at 2 different outcomes; yet both of these papers highlight the fact that, simply adding in 1 exercise into our athletes warm-up processes, that they can have a superior performance outcome in their chosen sports.

Firstly, I look at the addition of a simple exercise in a group of in-season athletes with patella tendinopathy that can significantly reduce pain levels to allow them to perform whilst on the road and away from their usual training facilities. Secondly, I look at a paper that highlights simply replacing a “usual” warm-up with 1 other activity can improve running times in a group of amateur endurance runners.

I sincerely hope you enjoy these 2 reviews (and the past 2 issues). I would love to hear your feedback and answer any questions that you may have, so feel free to reply to this email or email me at [email protected]

Patellar tendinopathy (PT) is a very common injury that affects training/playing availability and sports performance in athletes who frequently jump and land and change direction – such as basketball players and volleyball players. PT is characterised by localised pain at the inferior pole of the patella during jumping and landing activities; as opposed to a more diffuse area of pain reported around the front of the knee and kneecap in those who have patellofemoral pain syndrome (PFPS).

Historically, eccentric loading programs were advocated and prescribed for those athletes with PT. However, due to the provocative nature of these loading programs (especially when done in-season when training/playing loads are already high), they have fallen out of favour and replaced with less provocative loading protocols such as isometrics and heavy, slow, resistance (HSR) training (isotonics). With the benefits of being able to continue to train and play at a high level using both isometrics and isotonic options (Kongsgaard et al 2009, Rio et al 2015).

For athletes, and the medical/high performance teams, trying to manage PT throughout a competitive season, it can be quite challenging to adequately load the athlete to manage their symptoms, but also load them appropriately to maintain their ability to train, play and perform. These challenges are also made greater when training and playing “on the road”, without regular access to gym equipment and training facilities.

For these reasons, Ebonie Rio and her team of researchers wanted to investigate the effects of an isometric squat exercise (Spanish Squat) during the competitive season in elite and sub-elite athletes with PT over a 4-week in-season period.
The outcomes chosen to investigate the effectiveness of the program were:

PT pain (recorded as a numerical rating score of 0-10) during a single leg decline squat
PT pain and function as recorded by VISA-P questionnaire. VISA-P link here.
Adherence to protocol (recorded as number of times per week athletes completed the exercise)

The outcome measures as mentioned above recorded at baseline and each week for 4 weeks.

Methods
This study recruited both males and females aged 18 or over who participated in elite or sub-elite sport (eg. basketball, volleyball, AFL, tennis, badminton). To be included in the study that had to have a clinical diagnosis of PT, which is:

Pain localised and reported to inferior pole of the patella (does not move and spread)
Pain aggravated by energy storage and release activities such as jumping or fast change of direction
Minimum of 2/10 pain on single leg decline squat test (picture below)

NB: No restrictions were place on the length of time the athletes had the symptoms for.
As mentioned previously, the only intervention outside of what each athlete “usually” performed in-season in this research study was the performance of the Spanish Squat exercise. Each athlete was advised to perform 5 sets of 30sec of the Spanish Squat.

Due to the in-season nature of the study design and data collection, it was not feasible to have a “sham” or “placebo” intervention as the athletes had pain, were in-season, and were looking for pain and symptom relief. However, athletes that did not want to perform the Spanish Squat intervention were invited to act as a “control group” for this study.

Results
A total of 23 athletes had complete data sets, from a wide range of sports including AFL, Tennis, Squash, Basketball and Volleyball) agreed to participate in this study. 25 (19M/6F) athletes were originally enrolled in the study, however 2 (both female athletes) did not provide baseline or 4 week follow-up data sets and thus were not included in the analysis of 23 athletes.
In regards to exercise adherence, the Spanish Squat intervention was performed a median of 5x per week for all the 23 athletes; inferring that the exercise is easy to set-up and perform when travelling away from usual training and gym facilities.
The biggest positive of this study however came in the form of pain reduction in the athletes that performed the Spanish Squat. There was an average pain reduction of 49% on the single leg decline squat test from baseline to 4 weeks; which is a significant difference and a clinically important change.
The VISA-P scores also improved from baseline to 4 weeks; with a mean change of 18.8% being recorded across all the athletes performing the Spanish Squat. The authors report that a minimal important clinical difference for VISA-P ranges from 15-27%; so this number sits in that range.

Discussion
The findings of this study are really helpful for us working with in-season athletes who are struggling to train, play and perform with PT. The powerful effect that the Spanish Squat exercise can have on the athlete’s pain levels (NRPS) and function (VISA-P) is quite profound, and the fact that it was very well tolerated and accepted amongst the majority of the participants.
It would be remiss of me however to ignore the fact that at the end of the 4 week intervention, the mean pain score on the single leg decline squat for all the 23 athletes was still sitting between 3-4/10 pain. But when you consider that the mean pain score of all the athletes at baseline was between 7-8/10 on the single leg decline squat test, this 50% reduction in pain is significant to the point that it allows the athlete to continue to train, play and perform. The simple fact that 1 simple exercise performed 5x30sec on average 5x per week was able to achieve this huge reduction in pain is quite remarkable.
There were a few limitations to this study that the authors highlighted:

Not possible to recruit a control group or sham intervention due to the in-season nature of a mostly elite, professional cohort of athletes.
The intervention (5x30sec holds) was slightly less than previously reported successful protocols of 5x45sec holds (Rio et al, 2015). Would have been interesting to see if there was a greater change on pain scores and VISA-P scores with longer time under tension.

In summary, this study was one of the first of its kind to show that 1 simple exercise (the Spanish Squat) can help manage and improve the pain and function of in-season athletes who have PT. Even better, the exercise required very little equipment, is low cost, does not require any extra loading or gym equipment and can be performed anywhere, anytime.
Of course, there are many more facets to the thorough rehabilitation of PT, such as a comprehensive rehab program involving progressive overload and plyometrics – and no one is suggesting that doing the Spanish Squat is the only thing the athlete needs to do all year round – but it sure does give the athlete, medical/high performance team a very safe an effective treatment option for PT in-season, and specifically when “on the road”.

References:

Further readings

The performance benefits of resistance training in endurance runners has been demonstrated consistently over the last few years – most notably improved running economy over 3-5km distances (Yamamoto et al 2008, Paavolainen et al 1999, Spurrs et al 2003); however there are still ingrained beliefs held by endurance runners that resistance training can interfere with training (Yamamoto et al 2008).

Plyometrics have also been researched extensively and also shown in studies to improve running performance times and running economy, with the added benefit of requiring little physical space, time and equipment to carry out the desired training.

One of the most simplest forms of plyometric exercise is jumping rope where the person quickly rebounds on and off the ground. This type of plyometric training, requires very little equipment (skipping rope; no hurdles or boxes) and can easily be performed during the runner’s warm-up, making it more time efficient. Jump rope has also been shown to be more enjoyable to the endurance athlete, thus improving compliance and adherence to training (Ward et al 2007).

As there had been no previous papers looking at the effects of plyometrics within a warm-up in amateur endurance runners, the authors set out to determine the effectiveness of incorporating jump rope training during the warm-up routine of amateur endurance runners on jumping performance and 3km time trial performance; and other outcomes that would be difficult to measure outside of a laboratory (jump performance, reactivity and arch stiffness).

Methods:
105 amateur endurance runners (51 males and 45 females), aged between 18-40yrs (mean age 26.5yrs) were initially enrolled in this study. Inclusion criteria were:

Aged at least 18yrs
Able to run 10km in less than 50mins
Recreationally training between 3-5 running sessions per week
Not involved in any other resistance training program that included plyometrics
Had not suffered an injury in the last 6 months

The authors reported that to be included in the final analyses, each participant needed to complete the training program and be available for pre-post assessments. As a result, 9 participants could not fulfill these requirements; and were not included in the final analysis of 96 amateur endurance runners.

The 96 participants were randomly assigned to either the experimental group (usual running training and simply replacing their usual warm-up routine with jump rope) or the control group (usual running training and usual warm-up). Each participant was assessed at baseline (week 0) and then again at week 11 (post intervention) to monitor the changes over the course of a 10 week training program. See below for the progressive jump-rope training program.

In regards to outcome measures assessed – in particular the 3km time trial – each subject was tested 3-4 days prior to the study commencing and 3-4 days after the 10 week trial was completed. They were not allowed to eat 1hr prior to testing, or consume coffee 3hrs prior to testing. Testing was also conducted at the same time of day to avoid influence of circadian rhythm.

For the 3km time trial, each participant was tested individually and was conducted on the same 400m outdoor synthetic running track they were simply advised to run as fast as they could for 3km.
For jump performance, arch stiffness and reactive strength index (RSI), they were all measured in a controlled laboratory setting – details of these protocols can be found in the full text paper (email me at [email protected] if you would like the full text paper), but they are beyond the scope of this summary, as I try to highlight in all of my reviews the simple things we can do as clinicians in clinic without expensive lab equipment or expensive training devices.

Results:
The experimental group that conducted 10 weeks of a jump-rope protocol prior to running training sessions resulted in significant differences from baseline in all outcome measures including 3km trial times, jump performance (squat jumps, countermovement jumps, 30cm drop jumps), RSI and arch stiffness. Whereas, the control group subjects saw no significant differences from baseline in any of the outcome measures.

Discussion:
The aim of this study was to determine the effectiveness of a 10-week jump-rope training program that could be easily woven into the warm-up routines of amateur endurance athletes. The results clearly showed in this population of amateur athletes that simply replacing a “usual” 5min warm-up and replacing it with 5mins of jump-rope 2x per week (and gradually progressing up to 4x per week) can significantly improve many outcome measures, most notably 3km time trial, RSI and jumping performance.

Specifically, the jump-rope group improved their 3km running time by 23 seconds over the 10-week protocol, compared to 11.5 seconds improvement in the control group over 10 weeks of “usual” training.

These findings are fascinating and really highlight how a very simple strategy, such as 5mins of jump-rope, can replace other warm-up strategies such as body weight exercises, mobility exercises, stretching and slow jogging prior to a running session – and have a significant impact on running performance as well as jump performance, RSI and arch stiffness.

Given that these results were seen in an amateur population of recreational runners, it would generalise to the majority of runners that we would all see in our clinic each and every day.
From a practical perspective, if you and your athletes are anything like me and completely unco-ordinated and useless with a skipping rope and find yourself unravelling the rope from around your ankles every 10 jumps; to maintain a consistent tempo and continuous “bounce”, I would ditch the skipping rope and simply bounce up and down on the spot as if you were using a skipping rope.

References:

García-Pinillos F, Lago-Fuentes C, Latorre-Román PA, Pantoja-Vallejo A, Ramirez-Campillo R. Jump-Rope Training: Improved 3-km Time-Trial Performance in Endurance Runners via Enhanced Lower-Limb Reactivity and Foot-Arch Stiffness. Int J Sports Physiol Perform. 2020 Mar 12:1-7. doi: 10.1123/ijspp.2019-0529. Epub ahead of print. PMID: 32163923.

Yamamoto LM, Lopez RM, Klau JF, Casa DJ, Kraemer WJ, Maresh CM. The effects of resistance training on endurance distance running performance among highly trained runners: a systematic review. J Strength Cond Res. 2008;22(6):2036–2044. PubMed ID: 18978605 doi:10.1519/JSC.0b013e318185f2f0

Paavolainen L, Häkkinen K, Hämäläinen I, Nummela A, Rusko H. Explosive-strength training improves 5-km running time by improving running economy and muscle power. J Appl Physiol. 1999; 86(5):1527–1533. PubMed ID: 10233114 doi:10.1152/jappl.1999. 86.5.1527
Spurrs RW, Murphy AJ, Watsford ML. The effect of plyometric training on distance running performance. Eur J Appl Physiol. 2003;89(1):1–7. PubMed ID: 12627298 doi:10.1007/s00421-002- 0741-y
Ward P, Hodges NJ, Starkes JL, Williams MA. The road to excellence: deliberate practice and the development of expertise. High Abil Stud. 2007;18(2):119–153. doi:10.1080/13598130701709715

Thanks for reading and staying up to date. I look forward to sharing more in the future.

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