|Recovery in Training: The Essential Ingredient
Jonathan N. Mike, M.S. and Len Kravitz, Ph.D.
Recovery from exercise training is an integral component of the overall training program and is essential for optimal performance and improvement. If rate of recovery is improved, higher training volumes and intensities are possible without the detrimental effects of overtraining (Bishop et al., 2007). While recovery from exercise is significant, personal trainers and coaches use different approaches for the recovery process for clients and athletes. Understanding the physiological concept of recovery is essential for designing optimal training programs. As well, individual variability exists within the recovery process due to training status (trained vs. untrained), factors of fatigue, and a person's ability to deal with physical, emotional, and psychological stressors (Jeffreys, 2005). This article will provide evidence-based research and practical applications on recovery for personal trainers and fitness professionals
What is Recovery?
Bishop et al. (2007) define recovery as the ability to meet or exceed performance in a particular activity. Jeffreys (2005) continues that factors of recovery include 1) normalization of physiological functions (e.g., blood pressure, cardiac cycle), 2) return to homeostasis (resting cell environment), 3) restoration of energy stores (blood glucose and muscle glycogen), and 4) replenishment of cellular energy enzymes (i.e., phosphofructokinase a key enzyme in carbohydrate metabolism). In addition, the recovery is very dependent on specific types of training (see question #1 in the Pertinent Recovery Questions for the Personal Trainer section). Recovery may include an active component (such as a post-workout walk) and/or a passive component (such as a post-workout hydrotherary treatment).
Physiology of Recovery
Muscle recovery occurs during and primarily after exercise and is characterized by continued removal of metabolic end products (e.g., lactate and hydrogen ions). During exercise, recovery is needed to reestablish intramuscular blood flow for oxygen delivery, which promotes replenishment of phosphocreatine stores (used to resynthesize ATP), restoration of intramuscular pH (acid/base balance), and regaining of muscle membrane potential (balance between sodium and potassium exchanges inside and outside of cell) (Weiss, 1991). During post-exercise recovery, there is also an increase in 'excess post-exercise oxygen consumption' (or EPOC). Other physiological functions of recovery during this phase include the return of ventilation, blood circulation and body temperature to pre-exercise levels (Borsheim and Bahr, 2003).
Types of Recovery
The most rapid form of recovery, termed immediate recovery occurs during exercise itself. Bishop and colleagues (2007) give an example of a race walker with 1 leg in immediate recovery during each stride. With this phase of recovery, energy regeneration occurs with the lower extremities between strides. As each leg recovers more quickly, the walker will be able to complete the striding task more efficiently.
Short term recovery involves recovery between sets of a given exercise or between interval work bouts. Short-term recovery is the most common form of recovery in training (Seiler, 2005). Lastly, the term training recovery is used to describe the recovery between workout sessions or athletic competitions (Bishop et al., 2007). If consecutive workouts occur (such as within the same day) without appropriate recovery time, the individual may be improperly prepared for the next training session.
Connection to Fatigue
Fatigue is usually perceived as any reduction in physical or mental performance. However, when discussing various aspects of training, fatigue can be described as failure to maintain the expected force, or the inability to maintain a given exercise intensity or power output level (Meeesen 2006). Bigland (1984) expands that fatigue is any exercise-induced reduction in force or power regardless of whether or not the task can be sustained.
There are two types of fatigue: peripheral and central. Peripheral fatigue during exercise is often described as impairment within the active muscle. The muscle contractile proteins are not responding to their neural stimulation. Depletion of muscle glycogen (for fuel) is thought to be an important factor in peripheral fatigue, especially during prolonged exercise (Jentjens, 2003).
Central fatigue is concerned with the descending motor pathways from the brain and spinal cord. Bishop and colleagues (2008) explain that brain messages may signal reductions or complete cessation of exercise performance. A central fatigue hypothesis suggests that the brain is acting as a protective mechanism to prevent excessive damage to the muscles.
Other Associative Factors of Recovery
Gleeson (2002) elucidates the following related factors involved in the ability of a person to recover.
1) Muscle soreness and weakness
2) Poor exercise performance
3) Decrease in appetite
4) Increased infection
5) Quality and quantity of sleep
6) Gastrointestinal abnormalities
Personal trainers should be aware that these conditions may have an adverse influence on client recovery from exercise.
Pertinent Recovery Questions for the Personal Trainer
1) How Much Rest between Sets? Willardson (2008) describes rest between sets as a multifactorial phenomenon that is affected by several factors (see Figure 1).
However, summarizing previous research, he purposes some specific rest periods (between multiple set training) for the following training protocols.
Muscular endurance training: 30 to 90 seconds
Hypertrophy training: 1 to 2 minutes
Power training: 3 minutes
Muscular strength (for clients less adapted to strength training): 4 to 5 minutes
Muscular strength (for clients well-adapted to strength training): 3 minutes
2) How much rest between sessions? The greater the stress of the workout, the greater the overall muscle recruitment, and the greater the potential for muscle damage and soreness, therefore the need for longer recovery time. Muscle recovery between resistance training sessions for most individuals is also influenced by other types of training performed, such as cardiovascular training, interval sprints and sports conditioning sessions. Rhea (2003) concluded that for untrained individuals and trained individuals a frequency of 3 and 2 days, respectively, per week per muscle group is optimal, which translates to 1-2 days rest between sessions. However, this will vary depending on total volume of resistance training, individual training status, and overall goals (e.g., training for hypertrophy, strength, endurance, etc.).
3) Is there a gender difference in recovery? A gender difference has been shown in fatigue, a factor influencing recovery. Numerous studies have shown fit women have a greater resistance to fatigue than their male counterparts; therefore, fit women are able to sustain continuous and intermittent muscle contractions at low to moderate intensities longer than physically active men (Critchfield and Kravitz, 2008).
4) Do different muscle groups need more rest? Ground based movements such as the deadlift, squat, and overhead press require more rest than smaller muscle groups such biceps, triceps, and forearm flexors. This is due to the increase in motor unit recruitment and larger muscle mass involved with these multi-joint exercises.
5) Can certain supplements aid in the recovery of training? Many supplements have been used to assist in recovery of training. Bloomer (2007) provides evidence on certain antioxidants such as Vitamin C and Vitamin E and their purported affect on attenuating muscle damage, thus enhancing the recovery of training. However, he confirms that these supplements do not eliminate muscle trauma from exercise, only minimize some of the signs and symptoms (e.g., delayed onset damage, inflammation).
6) Does massage therapy affect the recovery process? Weerapong (2005) reported that some studies have shown that massage did in fact reduce delayed onset muscle soreness, while other studies have not realized this effect. However, it should be pointed out that the psychological benefits of massage toward recovery are often quite meaningful to the exercisers.
Bottom Line Message to Trainers
For client's to achieve optimal exercise performance, the personal trainer and fitness professional needs to be proactive in planning recovery into the training program. Although there is no consensus on a central strategy for recovery, monitoring and observing a client's exercise performance will always be most insightful in adjusting and planning for this essential ingredient of training. In addition, educating clients about the importance of recovery (such as proper sleep) may empower them to complete suitable interventions to enhance the process.
Jonathan N. Mike, MS, CSCS, NSCA-CPT, is a doctoral student in the exercise science program in the department of health, exercise, and sports sciences at the University of New Mexico (Albuquerque). He earned his undergraduate and graduate degrees in exercise science at Western Kentucky University (Bowling Green) and has research interests in strength and power performance, exercise and energy metabolism, exercise biochemistry, exercise endocrinology, and neuromuscular physiology.
Len Kravitz, PhD, is the program coordinator of exercise science and a researcher at the University of New Mexico, Albuquerque, where he won the Outstanding Teacher of the Year award. Len was honored with the 2006 Can-Fit-Pro Specialty Presenter of the Year award and chosen as the ACE 2006 Fitness Educator of the Year. He was recently presented with the 2008 Can-Fit-Pro Lifetime Achievement Award.
Bigland-Ritchie B, & Woods J.J. (1984). Changes in muscle contractile
properties and neural control during human muscular fatigue. Muscle and Nerve. 7(9): 691-699.
Bishop, P.A, Jones E., & Woods A.K. (2008). Recovery from training: a brief review.
Journal of Strength and Conditioning Research., 22(3):1015-1024.
Bloomer, RJ. (2007). The role of nutritional supplements in the prevention and treatment of resistance exercise-induced skeletal muscle injury. Sports Medicine. 37(6):519-32.
Borsheim, E & Bahr, R. (2003).Effect of exercise intensity, duration and mode on post-exercise oxygen consumption. Sports Medicine. 33(14):1037-1060.
Critchfield, B. & Kravitz, L. (2008). Fatigue resistance: An intriguing difference in gender. IDEA Fitness Journal 5(6), 19-21.
Gleeson, M (2002). Biochemical and Immunological Markers of Overtraining. Journal of Sports Science and Medicine. 1: 31-41.
Hicks, A.L, Kent-Braun, J., & Ditor, D.S. (2001). Sex differences in human skeletal muscle fatigue. Exercise and Sports Sciences Reviews, 29(3), 109-12.
Jeffreys, I. (2005). A multidimensional approach to enhancing recovery. Strength and Conditioning Journal. 27(5): 78-85.
Jentjens, R, & Jeukendrup, A. (2003).Determinants of post-exercise glycogen synthesis during short-term recovery. Sports Medicine. 33(2):117-144.
Meeusen, R, Watson, P., Hasegawa, H, Roelands, B, & Piacentini, M.F. (2006). Central fatigue: the serotonin hypothesis and beyond. Sports Med. 36(10):881-909.
Rhea, M.R., Alvar, B.A., Burkett, L.N., & Ball S.D. (2003). A meta-analysis to determine the dose response for strength development. Medicine and Science in Sports and Exercise, 35(3):456-464.
Seiler, S. & Hetlelid, K.J. (2005). The impact of rest duration on work intensity and RPE during interval training. Medicine and Science in Sports and Exercise, 37(9):1601-1607.
Weerapong, P., Hume, P.A., & Kolt G.S.N. (2005). The mechanisms of massage and effects on performance, muscle recovery and injury prevention. Sports Medicine, 35(3):235-56.
Weiss, LW. (1991). The obtuse nature of muscular strength: The contribution of rest to its development and expression. Journal of Applied Sports Science Research. 5: 219-227.
Willardson, J.M. (2008). A brief review: How much rest between sets. Strength and Conditioning Journal, 30(3): 44-50.