Recovery and Adaptation
In the previous post I discussed the interaction effect which occurs between strength and endurance training, and how strength gains are restricted at the molecular level in the muscle due to intense aerobic exercise. Optimal strategies exist to maximise strength gains, practically with appropriately scheduled training and nutritionally with ‘windows of opportunity’ in protein intake for maximal muscle synthesis and carbohydrate refuelling, for significant gains in strength improvement and ultimately performance.
The response to power, strength or endurance training stress is initiated at the muscle level, as suggested in concurrent exercise. The degree of adaptation is usually determined by the duration and intensity of exercise, either prolonged, intermittent or acute, and maximal, supra maximal or sub-maximal. The physiological response to exercise is also dependent on the training status of the individual, the genetic predisposition and the ambient conditions/ environment, hot or cold and altitude. This post will elaborate on the main issues surrounding recovery and adaptation and how interventions may help or hinder optimal adaptation in time for successive training sessions and long term performance gains.
Performance is nothing without recovery!
The ability to recover is probably one of the most important physiological traits to possess in performance cycling. Being ready to race again several hours after a hard session or event is crucial for success in back-to-back performances like stage races or double event weekends and even during competition. The potential for this develops during rest periods and is the main reason to focus on recovery to improve the level of training intensity and performance, termed supercompensation.
Biochemically, there is an increase in the expression of fat-burning enzymes, and increased resilience of the muscles, tendons and ligaments, an improved stroke volume and cardiac output of the heart I have previously written about the rationale behind supercompensation for smarter and more productive training here. The quality of recovery and duration determines when training can start again and at what fitness level. If recovery is too short then the individual risks entering into non-functional over-reaching (NFOR) or worse, Over-Training Syndrome. Conversely if recovery is too long, then fitness can be lost.
We can generally say that over the shorter term:
FITNESS = WORKOUT + RECOVERY
and longer term
FORM (PERFORMANCE) = FITNESS + FRESHNESS
Therefore recovery from a workout should be just as well managed as the workout itself, to find the right balance. This is easier said than done when the propensity of well-motivated individuals is to just train more often and harder. Incorporating recovery on a daily, weekly, monthly and yearly basis will make sure training productivity and optimal performance can be reached, whilst avoiding detrimental periods of over-doing it.
What causes adaptation?
After an intense work out, race or strength session, basically the microscopic environment of the cells looks like a biochemical ‘explosion’, with repair of fiber and proteins necessary, energy stores to be rebuilt and cellular chemistry to gain normality after intense contractions. Post exercise muscle protein synthesis can peak between 7 and 24hrs, but may only become normal 36hrs after.
Protein synthesis >> Protein degradation = INCREASED ADAPTATION
Protein synthesis << Protein degradation = MALADAPTION
Inflammatory mechanisms (such as those based on Cyclo-oxygenase/ Leukotrienes/ Prostaglandins) to cellular disruption and degradation caused primarily by mechanical and then secondary metabolic stress from Reactive Oxygen Species (ROS) which compromise muscle structures, are now known to be important mediators of recovery and positive response adaptations to training. In essence, adaptations are evoked primarily and mechanically through eccentric muscle action (calcium turnover and Calmodulin Kinase, CK) as well as metabolically through prolonged high energy turnover of ATP – ADP (AMPK) by rapid contraction as a secondary effect.
This is the sensitive point in recovery when the muscle capacity, through increased mitochondrial biogenesis (aerobic metabolism) and hypertrophy (size) combine to become temporarily stronger than before the training session was started. The principal of super-compensation demonstrates that chronic improvements in performance are due to an accumulation of the acute changes in the muscles over time. The muscles and connective tissues build themselves up to become stronger and resist further damage.
The exact physiological process of recovery remains unclear, the time course of the cycling muscles recovery to a general strength or high intensity endurance session can generally be indicated by the following:
- A decrease in Maximum Voluntary Contractions of the quadriceps 24-72h
- An increase in Delayed Onset Muscle Soreness (DOMS) 24-72h
- Leakage of muscle cell proteins- Troponin/ Creatine Kinase 0-144h
- Inflammatory markers Il-6 1-144h post exercise, C-Reactive Protein >24hrs post
- Oxidative stress – inflammation – marker?
Recovery interferes with adaptation
Recovery can be defined as the restoration of potential to perform at pre-exercise levels. Proper recovery allows adequate training stress and a positive super-compensation i.e. the ability to train at a subsequently stronger level. Many recovery strategies have been proposed to facilitate or even accelerate the adaptation to training, but their effectiveness is unclear. These include:
Milk A1/A2 Protein / hot or cold water immersion/ compression garments/ Inflammation Anti-oxidants/ NSAIDs/ Oxidative stress Vitamins ACE, Uric acid/ Allopurinol.
In fact, the Non-Steroidal Anti-Inflammatory Drugs Acetominophen, Paracetamol and Ibuprofen decrease the protein synthesis rate to training by potentially blocking the inflammatory response. A brief post explains this in more context for running. The signalling cascade involved is known to be important to adaptation response. It has also been shown that mitochondrial biogenesis & endurance capacity decreased with three weeks of Vitamin C supplementation. Again, this suggests free radicals ROS/RONS are needed for adaptation and supplementation with anti-oxidants may be detrimental to recovery, contrary to previous views and belief popular Vitamin A,C & E recovery drinks. High dose Vitamin C has also been misplaced as beneficial to the immune system in cyclists who are prone to acute upper respiratory infections. Anti-oxidant supplementation may only have a significant effect after extreme exercise or when approaching a state of overtraining. Even still, a high use of vitamins and minerals are taken to assist recovery after workouts, without sound understanding.
In practice, there is probably a bell-shaped distribution curve of the response of adaptation to oxidative stress caused by training. Low levels of cellular changes are beneficial until after maximal point, in which further reactive oxygen species actually have no further benefit or are even detrimental. This is known as hormesis. A sweet-spot may exist for each individual, hence an optimal strategy could be used to manipulate the stress response in favour of that athlete.
Supplements and recovery (Omega-3)
The benefits of carbohydrate and protein in recovery have been discussed previously, and aren’t worth repeating here in detail, although I can summarise:
The use of protein prior to, and during long term exercise has no benefit on rates of recovery after an intense session is completed. Generally 15-20g of protein and 80g of carbohydrate should be consumed within the first 30 minutes when rates of muscle glycogen synthesis and muscle protein are highest. Further intake of fruits/ vegetables and lean meats after 30 minutes with lower GI scores tend to maintain storage at lower rates.
I have previously touched upon the performance enhancing effects of Caffeine, Creatine and the Nitrodilator effects of the components of beetroot, and will do again at some point to catch up on a further scientific developments and application. Fortunately there is extensive research on these substances in the endurance performance setting (Bemben and Lamont, 2005), but this is not always the case. The validity of the use of these supplements has not been fully established through definitive trails, in contrast to that of more heavily regulated medicines for certain diseases or disorders. Even so, many athletes use them regardless of the efficacy and safety. While caffeine, creatine and nitrate loading prior to an event may have advantages in performance during said event, they tend to amplify the training stimulus or reduce the perception of fatigue. The use of omega-3 (PUFAs from fish oils and other sources) on the other hand, is a supplement which may facilitate enhanced recovery and can enhance the training effect achieved with a resistance training programme.
Omega-3 has anti-inflammatory properties and is involved in cell membrane signalling and intermediate signalling of the immune system. Improvement in oxygen efficiency during recovery and ADP kinetics in muscle mitochondria has been observed as a possible mechanism of enhanced performance when taking Omega-3, although no study (as of December 2015) has demonstrated any beneficial effect on endurance exercise performance in well trained individuals. Some effect has been seen on VO2peak in untrained individuals. Most interestingly, Omega-3 given at 4g per day for 8 weeks in master female athletes >65years old has shown an increase in Muscle Protein Synthesis greater than 60%. Suggesting substantial impact on nutritional response to MPS and greater training induced strength gains in this group compared to control. This potentially has very positive applications in master athletes, with anabolic resistance to muscle growth undertaking strength training. It seems to gain positive effects from Omega-3 supplementation, dosing should be at least 3g per day for at least two weeks, to increase levels in the muscles.
Many ‘nutriceuticals’ lack the integrity from regulatory approval of manufacturing to prevent contaminants, maintain purity and assess risk/benefit in studied individuals with particular characteristics representative of the general population or not, before they are marketed. Advanced protein matrices such as whey, soy and casein plus also BCAAs and vitamin C make up for over 15% of products consumed by the performance sports market. Coverage of their use and the performance market is growing, and serves as its own yard stick to internally measure their advantage of use for recovery and adaptation. I’ll enter into more detail on the science of protein and BCAA’s in my next post, but it seems current research and real world experience seems to show benefits which are generalisable to the broader population.
Active Recovery Strategies- Positive and Negative
The applied perspective of supercompensation is not straight forward in real world practice as there are so many variables. We need to measure fatigue, recovery and freshness to know if someone has recovered or not, but don’t want to get caught up in the numbers too much. Getting the basics right e.g. enough sleep (7-9 hours) for growth hormone release, quality rest/ napping and not letting the diet slip is more important and effective than belief in a new recovery intervention. Simple considerations such as inclusion of maintenance of endurance sessions in strength periods or avoidance of the menstrual cycle in female athletes may help avoid erratic recovery and performance. Field tests are a good way of tracking acute recovery, based on power/ heart rate in between more formal testing over a season. Recovery and adaptation are also tied closely with over-training such that inadequate recovery can often lead to training stagnation and burn-out as too many cyclists train too hard and recover too little. A well periodised training programme should include progressive overload with recovery phases to permit physiological and psychological regeneration.
Passive recovery, without any purposeful action has been demonstrated to be inferior to more well established active recovery interventions. Active recovery such as very light spinning, walking, stretching, swimming, massage (non-traumatic/ or deep tissue), hot and cold showers have been associated with:
- increased heart rate/ blood flow
- increased inflow of nutrients
- reduced soreness
- lower blood pressure
- a relaxed central nervous system
Alternating between cold-water immersion to reduce inflammation, and warm-water immersion to increase blood flow and accelerate recovery is known as contrast bath therapy, and has probably been borne of anecdotal evidence rather than solid evidence. Studies in cold water-immersion and alternating immersion (1 min at 15oC and 1 min at 38oC) have seen some benefit as a recovery intervention compared to passive recovery, after hard resistance exercise. Sprint power was slightly improved in one study looking at cold and alternating baths, after intense endurance sessions for five consecutive days but was not statistically significant. Time trial performance showed similar results versus passive and hot-water immersion. Cold water immersion is potentially quite beneficial to rapid recovery and repeated competition (stage racing) or within a single day by preventing any decline in performance. It is probable, that the effect from alternating cold/warm bath immersion comes from the cold-immersion component. Also that the lowering of body temperature will be more accelerated in riders who exercise in hot environments as opposed to a slower cooling of body temperature which may precipitate heat related illnesses over successive training sessions. The apparent effect of cold water immersion on performance may well be due to reduced perceptions of pain which may help elicit better performances.
Other recovery and adaptation strategies, include the use of hypoxic stress, known (see post) to amplify the metabolic response to endurance training, in a similar way to blood occlusion techniques which are controversially used in hypertrophic sport. Similarly, compression garments are popular post-training recovery interventions. The rationale behind the application of compression socks and tights, is that the increased pressure around the limbs may improve circulation, reduce swelling and inflammation, and accelerate removal of waste products and increase venous return while at rest, and even assist performance economy or efficiency during exercise. There is minimal well designed research into the effectiveness of modern compression garments in cycling, but these may have a better application in running in lowering the energy cost of running at lactate threshold pace. However, in general there has been no significant overall effect of compression garments on physiological and performance reported. Subjective feelings of alleviated muscle soreness may result in higher self-paced performance (which may possibly lead to over-training) could account for anecdotal reports of benefit of their use. X-Bionic garments are a recent addition to the commercial market and are partial-compression based, also designed to optimise thermoregulation for both cycling and running. I’ll be looking more closely at this brand in the near future as they claim some considerable improvements in physiological parameters and performance benefit.
One final modality of recovery that doesn’t get too much attention for its benefit, is physiotherapy and soft tissue mobilisation. Preparing the muscles through treatment can happen in-between endurance sessions when strength work is minimal. Improving blood flow and passage of nutrients/ waste products can have large impact on physiological performance parameters such a cycling economy and lactate threshold.
Hence significant consideration given to which recovery strategies should be applied, when and for what potential benefit, if any maybe gained. Manipulating stress responses via recovery strategies potentially aligns for faster recovery whilst maintaining physiological adaptations necessary for similar or improved performance. Full recovery can usually be defined by typical signals, desire to undertake training, normal resting heart rate, increased heart rate variability, quality sleep and balanced emotions.
Acute and chronic training to improve performance:
- Causes stress responses, muscle damage – both mechanical and metabolic.
- Stress response elicit repair processes – microcellular and hormonal, and inflammatory mediated?
- Repair processes result in muscle re-modelling, growth, adaptation and ultimately supercompensation.
Little is known about the mechanisms involved in physiological adaptation and whether inflammation has a negative or positive influence on evoking these training adaptations. Stress responses to exercise depend on several factors and different time courses. Stress responses are important to recovery adaptation, and should not be eliminated entirely. Ideally, recovery for optimal adaptation should incorporate passive rest or mild activity along with sufficient nutrition and adequate sleep hygiene. The application of additional ‘popular’ recovery strategies to cyclists should be warranted on an individual preference as a subjective experience may well be just as beneficial psychologically as that of any potential physiological gains, which could easily be connected as we find out more about our neural (CNS) control and regulation of our bodies.
Recovery should be individualised, as the amount of time to reach full recovery is not only dependent on the type of workout but also the riders inherent potential and state of fitness. Recovery is faster with greater fitness. Different strategies are best off practised in training. In reality, full recovery is rarely ever achieved, and the overlap may assist in the development of fitness which leads to supercompensation, when adequate rest is finally introduced. This ultimately can provide better preparation for longer and more challenging events when performed under a well structured training programme.Leave a reply →