Fantastic plastic: rolling to win

The birth of the transistor back in 1947 was without doubt one of the most important technological developments of the 20th Century. Without silicon transistors, the construction of small complex circuit boards and fast processors – essential components of the computer – would have been impossible. No computers, no internet, no email, no mobile phones, no social media; you get the idea.

But the first half of the last century saw another rapid advance in technology that was to change our world. Today, you take them for granted, but without the development of plastics, life in the 21st Century would be very different. PVC, polythene, polystyrene, Teflon and nylon are all compounds developed in that era - compounds and materials that are now essential for everyday modern life.

The fitness plastic

Although you might not have thought about it, the use of plastics has found its way into many aspects of sport. If you use training shoes of any description, you can bet your bottom dollar that they’ll be reliant on plastic technology. One of the best examples is the polymer called ethylene vinyl acetate – better known as EVA to most of us. Unlike most plastics, EVA can be used to construct a solid, yet supple and compressible foam – perfect for running shoe soles. And although there are other polymer plastics in use, it’s fair to say that over the years, the cushioning qualities of EVA have protected more runners from more injuries than any other plastic!

But the wonders of EVA use don’t stop there. Add a bit of cross linking during the synthesis process and you get ‘closed-cell’ EVA foam, a light and hard, but strong and resilient foam. Triathletes and swimmers will be familiar with closed cell EVA foam as it’s the staple material for kickboards. But there’s another fitness use for this type of closed-cell EVA, and one that many of you may be familiar with – foam rollers. A simple cylindrical shape constructed of closed cell EVA foam, the foam roller has become increasingly popular with athletes who need to reduce muscle and connective tissue tension either before or after training/competition. This process of foam rolling stretches the tissue and creates friction, in a similar manner to a conventional massage⁽¹⁾. But just how effective is foam roller use? And can it really help dissipate muscle tension and improve performance?

Foam rolling research

During foam rolling, connective tissue known as the ‘fascia’ is rolled, stretched and compressed, utilizing the athlete’s own body weight to apply pressure to the soft tissues. The term fascia refers to the fibrous connective tissue that penetrates and surrounds muscles (sheathes), organs, bones, nerves, and blood vessels, to form a complex, three-dimensional network. Research has identified that this fascial tissue is not simply passive connective tissue; rather it is a dynamic, contractile tissue, which plays a key role in how we move.

Particularly relevant is the fact that trauma, inflammation, or immobility can cause the fascia to lose flexibility and become restricted or ‘sticky’, resulting in fascial tissue imbalances, pain, or joint dysfunction⁽²⁾. Furthermore, optimal fascial tissue function is needed for smooth inter-muscular gliding and movement efficiency^(3,4). In short, ‘sticky’ fascial tissue can increase internal friction and make muscular movement less efficient (bad for performance).

A number of physiological studies have concluded that foam rolling increases mobility, promotes blood flow, improves vascular function, and that it may also increase parasympathetic activity after exercise (the process by which the body switches into recovery mode). This in turn can reduce inflammation and fascial tension, and aid recovery⁽⁵⁾. The claim of improved vascular function following foam rolling is supported by ultrasonography (ultrasound) research demonstrating significant increases in arterial tissue perfusion and blood flow velocity immediately following self myofascial release (SMR – achieved by foam rolling)^(6,7).

Longer-term benefits

In theory, an improved blood flow through muscles improves the capacity for post-exercise lactate removal from the working muscles into the vascular system, thereby speeding recovery. This seems to be verified by a recent thermal imaging study, which found SMR significantly enhances metabolic recovery by accelerating lactate reduction and normalizing muscle temperature (and being more effective than passive recovery strategies)⁽⁸⁾. However, in addition to acute post-exercise recovery benefits, some researchers have suggested that regular SMR may have longer-term performance benefits due a combination of the following overlapping mechanisms:

·        Improved neurological responses in fasical tissue(pain relief and parasympathetic shift).

·        A “fluidization” of the ground substance in between fascial layers, and breakdown of sticky adhesions (reducing internal friction). In short, when subjected to regular foam rolling, fascial tissue can become more fluid, which can reduce internal resistance during repetitive movements such cycling⁽⁹⁾.

·        Faster metabolite (eg lactate) clearance.

·        Reduced perceived soreness, shortening the recovery time needed between high-quality training sessions.

However, while short-term studies have demonstrated transient improvements in range of motion and reduced delayed-onset muscle soreness (DOMS) in sports such as cycling, the evidence for longer-term performance gains in cycling has been either anecdotal or limited to short interventions. The question that hasn’t really been answered is “Can adding self-myofascial release (SMR) via foam roller after every training session produce measurable performance gains in already-trained endurance athletes beyond the effects of a structured endurance program training alone?” The good news however is that we can turn to brand new research to get a definitive answer.

New research

Scientists from the Department of Sport Science at the University of Innsbruck, Austria decided to investigate the performance benefits or otherwise of a long-term, 6-month program of foam rolling in fit, recreational cyclists⁽¹⁰⁾. Published in the journal ‘Sports’, the researchers set out to discover whether regular foam rolling as part of a cycling program could improve any of the following metrics of performance:

·        Maximum aerobic capacity.

·        Better (reduced) heart rates while cycling at submaximal paces (lowering the workload at a given pace).

·        The rate of lactate clearance from working muscles.

·        The power output at first and second lactate thresholds (ie the cyclists’ watts/kg at the 2mmol/L (aerobic) and 4mmol/L (anaerobic) lactate thresholds.

To do this, 32 male recreational road cyclists, aged between 25 and 59, were recruited for the study. While classed as recreational, these were nevertheless serious cyclists, with at least three years of cycling training background, averaging eight to ten hours per week of training time in the saddle, and a weekly mileage averaging 150 to 190 miles per week. Importantly, none of them had practiced SMR using foam rolling prior to the study.

What they did

The cyclists were randomly allocated into one of two groups of 16 – a control group following a standardized training program and another group, following the exact same training program but with the addition of foam rolling after training. As for the training program, both groups performed four sessions per week: two long low-intensity rides, and two interval training sessions, with a total of around nine hours per week. There was a progressive 5% increase in load every four weeks, and all sessions were heart-rate and perceived-exertion controlled (monitored via Garmin Connect and training diaries). To minimize error, all the cyclists underwent standardized bike fitting two weeks before the start of the study to ensure their riding position was optimized for the training and testing.

Foam rolling protocol

As stated, the both the control group and the intervention group performed the same training program outlined above for six months. However, the foam rolling intervention group additionally undertook the following foam-rolling protocol:

·        Around 40 minutes of structured SMR immediately after every cycling session using a standard 30 cm Blackroll® foam roller.

·        Twelve exercises in each foam rolling session targeting the entire lower-limb kinetic chain, including the plantar fascia (base of the feet), calves, tibialis anterior (shin – see figure 1), hamstrings, quadriceps, adductors (inner thighs), iliotibial band (outer thigh), gluteals (buttocks), and lumbar fascia of the lower back.

·        All foam exercises were performed at a slow 3cms per second rolling speed, 20 repetitions per set, two sets per exercise, with 30 second pauses between sets.

·        Enough pressure was applied to generate a target pain rating of 5 to 7/ on the 1-10 numeric rating scale. (see figure 2)

·        To ensure a good technique, all sessions were video-guided and compliance averaged over 92%.

Figure 1: SMR foam rolling for tibialis anterior (shin)