5 must-read research reviews on recovery by Science for Sport

SPECIAL EDITION 5 must-read research reviews on recovery

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Page Number

Section

Link to Abstract Review Title

Study Details

Practical Takeaways from study

Related links to learn more about the topic

Reviewers comments on the study

Fatigue & Recovery

[Abstract]

How sleep impacts strength gains, and what we can do about it OBJECTIVE Sleep deprivation and sleep restriction both increase fatigue and decrease readiness to training. At present, there is limited knowledge surrounding the effects of inadequate sleep on strengthperformance. Therefore, the aim of this systematic review is to understand the effect of sleep deprivation and sleep restriction on resistance training performance, and to explore the effects of inadequate sleep on hormonal responses and markers of anabolism. WHAT THEY DID The authors performed a systematic review which included studies based on three combined concepts: 1) inadequate sleep, 2) resistance exercise, and 3) performance and physiological outcomes. WHAT THEY FOUND With regards to acute sleep deprivation (e.g. one night with no sleep), there seems to be no significant detrimental effect on muscle strength. Moreover, there also seems to be no alterations on the cortisol-testosterone profiles following acute sleep deprivation. However, studies investigating chronic sleep deprivation (i.e. 30-64 hours of no sleep) found mixed results. For example, two studies observed a reduction in strength, and one study reported no differences in strength in comparison to a control group.

Practical Takeaways Acute sleep deprivation (e.g. one night with no sleep) appears to have no detrimental effect on strength; though there is limited research on this topic. On the other hand, extended sleep deprivation does seem to have a harmful effect on strength, with consecutive nights with reduced sleep affecting multi-joint strength. Napping before resistance training sessions and changes in training schedule (e.g. late starts) can be effective strategies for minimising the impact of sleep deprivation on performance during periods of inadequate sleep. Lastly, group training and the consumption of caffeine can increase resistance training performance; however, care must be taken with caffeine intake if athletes are training late in the day (i.e. mid-afternoon onwards) as caffeine can negatively impact sleep.

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Francisco’s Comments “The authors of this study highlight a particular scenario in which athletes are likely to be subject to sleep deprivation – the birth of a new child. I can relate to this scenario as a lot of my athletes have had to deal with sleep restriction/deprivation as a result of newly-born babies. Some other scenarios that may lead to inadequate sleep include: important competitions, especially for novice players, school and work-related stress, jet-lag, higher than usual training load. Practitioners must be able to identify these type of scenarios (e.g. inadequate sleep) and implement counteractive strategies such as: 

Adjust resistance-training loads



Adjust the training schedule (e.g. late starts or inclusion of napping opportunities)



Implement competition within training sessions (e.g. competition in some exercises)



Pre-training nutritional strategies (e.g. caffeine intake)



Training in groups

Although research is limited regarding the hormonal responses to sleep deprivation, it seems that chronic sleep restriction may lead to an inappropriate hormonal environment for adaptations to resistance training. Further research is needed to better understand the effects of inappropriate sleep on anabolic responses. Moreover, it would be interesting to explore the effects of inadequate sleep on muscle activation.”

Fatigue & Recovery

[Abstract]

Sleep extension through napping may effect performance OBJECTIVE

WHAT THEY DID

WHAT THEY FOUND

Day napping is a strategy frequently used by athletes to increase sleep duration and readiness to perform. Although, there seems to be little scientific evidence about the effects of naps aiding athletic performance and the effects of different napping durations on subsequent performance.

Seventeen physically active men performed a shuttle test under four conditions with 72-h between each condition: 25-, 35- or 45-min nap opportunity (NAP25, NAP35, NAP45, respectively). No nap opportunity (CON).

The main findings of this study were:

This study aimed to investigate whether or not different nap durations aided an athlete’s readiness to perform on the same day.

 The main practical takeaway of this study is that athletes may benefit from a nap during the day-time before practice or competition.  Some points must be considered when allocating a time for naps to occur in the training schedule:  Naps should occur early in the afternoon (~13:30-16:00) in order for future sleep to not be affected.  Naps should not be long (~20-30 min) so night sleep is not affected.  If napping is to be included in athlete’s routine, practitioners need to ensure that athletes have the facilities to allow for this.

effect on BD in comparison to CON.

 All napping conditions were beneficial on TD in comparison to CON.

 No effects of any condition on FI.  RPE was lower in NAP45 in

The shuttle test consisted of six sets of comparison to CON and NAP25. 30 sec maximal shuttle sprints over 5-,  No effects of any conditions on 10-, 15- and 20 m with 35 sec between sleep quality during the nap sets. Total distance over the 6 x 30 sec opportunities or preceding nights. (TD), best distance (BD) and fatigue index (FI; FI (%)) were obtained. For specific information on how FI was calculated refer to the abstract link above.

Practical Takeaways

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 NAP25 and NAP45 had a beneficial

Francisco’s Comments “Although the participants of this study weren’t athletes, the conclusions from this study still provide us some guidance in terms of the effects of napping in performance. More precisely, this study demonstrates that napping during the day may provide benefits in terms of athletic performance. In previous issues, I have talked about the importance of providing group (Performance Digest Issue #28) and individual education about sleep hygiene and strategies to enhance sleep time and sleep quality (Performance Digest Issue #32). Increasing total sleep duration by adding naps can be a powerful tool to be used in athletes revealing bad sleep duration and quality. These athletes can trial day napping and understand how it effects their fatigue levels and night sleep. Practitioners need to be aware that for some individual’s day napping may negatively impact on night sleep and, therefore, effect their overall sleep duration/quality.”

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Technology & Monitoring

[Abstract]

Which day of the week should we schedule lower-limb strength training? OBJECTIVE Coaches are always searching for the best way to sequence training methods during a competitive season in order to reduce unnecessary fatigue and improve performance. After games, coaches are looking to manage the need to get in training while facilitating recovery after intense loading. If sport science can discover how the body responds to the timing of common load prescriptions, coaches can design better workouts that are in harmony with the recovery cycles after games and before the next match. The goal of this article was to find out what sequence of lower-limb injury prevention training facilitated the best recovery profile between matches. WHAT THEY DID The researchers staggered workouts with semi-professional soccer players so they could see how different timing strategies after games influenced fatigue patterns before the next match. The scientists ensured that the workouts and practices were similar enough to properly compare, and they also evaluated fatigue using jump analysis as well as creatine kinase (i.e. a muscle damage biomarker). The athletes were divided into three groups and each of them experienced all three timing experiments, including a rest day control. Isometric strength and perceptual recovery were also tested. The exercise protocol consisted of 4 exercises; lunges, single stiff-legged deadlift with 6 kg kettlebell, single-leg eccentric squats (all 4 x 5 repetitions on each limb), and Nordic hamstring exercises performed on a Bosu-ball (4 x 5 repetitions). WHAT THEY FOUND The investigators found that placing training earlier in the week resulted in a superior recovery rate if they are only employing injury reduction exercises. Specifically, the inclusion of the Nordic hamstring exercise, an eccentric overload option in training, wasn’t taxing enough to interfere with both training and competition.

Practical Takeaways If you are tapering a team for playoffs/ championship play or follow a programme that uses very low volume and intensity, then it’s a good idea to place the lower-limb strength training closer to the last match played. Another idea is to consider the use of creatine kinase testing in conjunction with force plates, as the pairing may create a repeatable micro-cycle set-up that is useful for in-season training. Also, working with a team coach is recommended to ensure the sequence and loading is similar, otherwise the responses may not be the same as the study.

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Carl’s Comments “What is important, is that coaches should revise the workouts used in this study and decide if they are similar enough to your own and that the conclusions are relevant to your programme. I feel that this workout structure is not appropriate for team-sports such as Rugby and American Football, but it might suffice for programmes that conform to minimal weight training (e.g. semi -professional football [soccer]). It would be nice to repeat the study with programmes that are successful using higher intensities and volumes to see if the same conclusions are found.”

Fatigue & Recovery

[Abstract]

Foam rolling increases passive range of motion but decreases muscle strength OBJECTIVE

WHAT THEY DID

Foam rolling (FR) is widely implemented by athletes to improve range of motion (ROM) and speed-up recovery. Evidence demonstrating the effects of FR increasing passive ROM and decreasing acute fatigue are scarce. This study aimed to analyse the acute effects of two hamstring FR volumes on knee extensors fatigue, and to analyse the effect of hamstring FR on shoulder ROM.

Twelve women were exposed to two experiments:



To measure the effect of two hamstring FR protocols on knee extensor fatigue, and



The effect of hamstrings FR on shoulder flexion and extension ROM.

For the first experiment, the subjects performed 3 conditions on 3 different occasions, which included:



FR for 60 sec (FR60), 120 sec (FR120), or no foam rolling (control (CON)).



The subjects performed 3 sets of knee extensions (based on 10 RM load) to failure of followed by one of the conditions (FR60, FR120, or CON) during the 5 min rest period between sets.

WHAT THEY FOUND For the first experiment, fatigue index (calculated by the difference in reps performed on the 1st and 3rd sets) were higher in both FR60 and FR120 in comparison to CON, however, there were no differences in the fatigue index between the two FR conditions. For the second experiment, it was observed that FR applied to the hamstrings influences both shoulder flexion and extension ROM.

For the second experiment athletes performed FR60 and shoulder flexion and extension ROM was measured before and at 0 min, 10 min, 20 min, 30 min, 24 h and 48 h after the protocol.

Practical Takeaways The main takeaways of this study are:

⇒ FR may have an acute effect on fatigue and ROM due to centrally mediated mechanisms.

⇒ FR for 60 sec or longer may influence the antagonist muscle force production (i.e. decrease resistance to fatigue).

 FR for 60 sec may influence the ROM of joints that are not crossed by the muscles that were exposed to FR (i.e. FR on the lower limb affect the ROM of upper limb). Increasing ROM of joints without FR the muscles of that joint can help practitioners during rehabilitation processes.

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Francisco’s Comments “In the current sporting envrionment it is rare for an athlete to not use FR as part of their training preparation or recovery routine. Research has demonstrated that FR performed before exercise increases ROM. It has also shown that it helps with recovery from muscle soreness and attenuate the reductions in muscle performance after exercise. This study demonstrates that performing FR in an agonist muscle can lead to a decrease in performance in the antagonist muscle. It may be possible that FR performed in a non-athletic population leads to a tissue trauma, therefore impacting on performance. This being the case, the results from this study wouldn’t stop me from using FR in well-trained or recreationally-trained subjects. I have previously used FR and other types of selfmyofascial massage with my athletes before training sessions. For time efficiency, I have targeted the muscle groups that would be more involved in that session. Interestingly, this study demonstrates that FR one muscle group will increase ROM on other joints. I think it would be very helpful to understand if the changes in ROM would be greater in the joints crossed by the muscles where FR was used, in comparison to other joints (e.g. FR the hamstrings and quadriceps and measure changes on hip flexion and shoulder flexion ROM).”

Strength & Conditioning

[Abstract]

How little can you train and still get stronger?

OBJECTIVE

WHAT THEY DID

WHAT THEY FOUND

The concept of “minimum effective dose” has been explored in volume and hypertrophy, however, in trained individuals, the minimum effective dose for increasing 1RM has not been adequately examined. Reviewing the available evidence on what the minimum resistance training a person can do and still improve 1RM strength may be of great benefit to athletes and coaches looking to increase or maintain strength during limited training time periods.

The study criteria for inclusion was:

All of the identified studies reported, significant increases in strength for the lowest volume group (1 set per week, 612 reps per session, 1-3 sessions per week) of 12.04 kg for the squat and bench press together. Higher volume groups experienced approximately 50% greater 1RM increases than lower volume groups (3-8 sets, 4-12 reps per session, 1-3 sessions per week).

Thus, this study aimed to systematically review the available evidence regarding the minimum effective training dose required to increase 1RM strength.

1) Randomised trial. 2) Resistance training intervention lasting a minimum of 4weeks manipulating training variables. 3) Maximum of one working set per exercise per session. 4) Healthy male subjects with at least 1 year of resistance training experience. 5) At least one of the powerlifts included. 6) A 1RM test used before and after the intervention.

Five of the included studies required participants to reach momentary failure while one study instructed participants to reach volitional failure. As percentage of 1RM loading was not reported, it was assumed loading was 70-85% 1RM based on reaching failure for prescribed sets/reps.

The literature search used PubMed, SPORTDiscus, and Google Scholar databases. The following terms were used: “training volume” AND “powerlifting” OR “1RM strength” OR “powerlifters” OR “low volume” AND “powerlifting” OR “1RM strength”, “high vs. low volume” AND “powerlifting” OR “1RM strength”, “minimum effective training dose.” Of the 2368 articles found, 38 full texts were found to be relevant with 6 studies being included for analysis.

Practical Takeaways The results of this study may be applied in a couple sporting settings: 

Periods of high frequency or high importance of competition (e.g. World Cups), allowing adequate recovery whilst maintaining general strength levels and addressing more important components of the sport, such as technical/tactical or speed/power.



In athletes that already possess a strong general strength base where other components of fitness or more specific strength work want to be addressed.

A 4-week cycle could be a simple linear progression: 

Week 1: 70% 1RM @ RPE 9-9.5



Week 2: 75% 1RM @ RPE 9-9.5



Week 3: 80% 1RM @ RPE 9-9.5



Week 4: 85% 1RM @ RPE 9-9.5

It is less clear whether these improvements may be achievable in the deadlift 1RM or in trained women or highly trained strength athletes due to lack of current evidence.

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James’ Comments “Minimum effective dose is often talked about as the way to develop physical qualities with minimal fatigue. “Slow cooking” the athlete is one way to put it. However, as shown in this study, “slow cooking” could be changed to sub-optimal when referring to strength. A minimum effective dose for strength training could be useful in the scenarios presented above. However, if training periods are planned correctly, there’s no reason greater volumes can’t be used to eek out that extra 50% strength gain alongside developing other physical capacities. Minimum effective dose seems to work best with activities of maximal intensity done regularly throughout a week such as sprinting.”

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