Timing of Training, Overtraining and Recovery

Question 1

Variation in Exercise Responses

Answer 1

• Heterogeneity or variability in exercise adaptation responses is well known (whether it be resistance or endurance training).
• A study by Hubal et al. [1] showed the wide ranges of response to resistance training, some showing little to no gain, + others showing profound changes.
• Has led to the development of terms such as “non”, “low,” “moderate”, “high”, + “extreme” responders to a given exercise stimulus
• Diurnal circadian oscillations in selected gene targets, transcription factors + hormones may explain the heterogeneity or variability in resistance training adaptations.
  For example:
• Higher responders in hypertrophy to a 16-week resistance training program exhibited either higher basal (i.e., pre-training) or post-intervention increases in MyoD (myogenic determination factor 1) + myogenin transcripts, respectively [2, 3).
• Transient, but chronic, elevations in MyoD + myogenin gene expression in training sessions may be needed for greater muscle hypertrophy [2].

Question 2

A Time for Muscle Hypertrophy? = why there might be a timing effect for targeting muscle hypertrophy

Answer 2

• Lower cortisol levels following resistance exercise in the evening compared to the morning [6, 7].
  ○ Is catabolic, want an anabolic env = growth
• Reduced catabolic envs to promote muscle hypertrophy adaptations - increased circulatory secretion of IGF-1 for subsequent activation of p70S6K etc. [5] = leads towards increased protein synthesis
• Potential for enhancing muscle anabolism when resistance exercise is performed in the evening compared to morning.

Question 3

Kuusmaa. et al. [8] conducted a study involving 24-weeks of combined strength (S) + endurance (E) training performed in the morning versus afternoon (in young untrained men).

Answer 3

• Larger gains in muscle CSA
  were found in the evening
  training groups compared
  w/ the morning groups,
  irrespective of the exercise
  order.
• Suggests there is some type of timing effect
• More favourable conditions in evening for testosterone
  = Testosterone = anabolic hormone
• When there is a ratio that promotes higher increases in testosterone compared to cortisol = we say it’s a more favourable anaerobic env

Question 4

Diurnal rhythms in testosterone + cortisol remained statistically unaltered by the training order or time [8].

Answer 4

• In the evening = the group that performed endurance followed by strength = showed a greater improvement in perf
• Wasn’t a time-of-day effect = but there was a sequence effect
• More of a programming aspect rather than something that’s relying on someone’s circadian rhythm
• Endurance perf development favoured the endurance followed by strength order w/ no differences for time of day [8].

Question 5

Time of day + exercise order did not influence the magnitude of adaptations in maximal dynamic strength perf (increases ranging from 14-24%) [8]

Answer 5

• Max isometric voluntary force (MC) measured on leg-press was different at post- compared w/ pre-intervention (* p<0.05) BUT no differences b/w groups.
• Although Sedliak et al. [9] found no differences in muscle hypertrophy between morning versus afternoon training, p70S6K was higher in the morning group.
• p70S6K is involved in a signalling pathway that positively regulates muscle growth.
• May compensate for some other contributing factors (e.g., hormonal, metabolic, myogenic) that are less/more activated in the morning compared to afternoon.

Question 6

Effectiveness of Resistance Training in the Morning versus Evening Hours

Answer 6

Muscle hypertrophy
* 5 studies w/ a total of 10 groups
* no significant dif b/w morning + evening resistance training groups for muscle hypertrophy
* A degree of caution is warranted when extrapolating these results into practice given the low number of studies

Question 7

A Time for Muscle Strength?

Answer 7

• Previous studies have shown that greater improvements in maximal strength perf occur at the time of day at which resistance training was regularly performed [11-13).
• Thus, there appears to be a temporal specificity to resistance training for muscle strength development

Question 8

MUSCLE STRENGTH

Answer 8

Baseline:
* Muscle strength peaks b/w 1600-2000 h
- Consistent findings
* Muscle strength peaks in evening
- Irrespective of muscle group measured or speed of contraction

Question 9

Handgrip

Answer 9

• Moderately correlated w/ lean body mass + whole-body strength
  ○ In a clinical pop can be a marker of whole body strength
• A ‘marker rhythm’ in chronobiology
• In the earlier part of the day = small amount of reduced perf
• Then as get to around the midday period = pretty consistent up towards early morning
• What pop would you not use a handgrip test? = some athletes = not really sport-specific
• Why wouldn’t it give you a good indication on an athletes ability to run faster or jump higher? = not specific = are dynamic movts not iso

Question 10

Is Core Body Temp Responsible for the Time of Day Difference in Muscle Strength?

Answer 10

• Maximal isometric strength at six time points throughout a 24-h day:
  –> changes in strength correlated w/ the changes in CBT
• Passive heating of CBT not sufficient to increase morning maximal isometric strength
• Increasing CBT through increased physical activity resulted in no significant increase in morning maximal isometric strength

–> time-of-day changes in CBT do not account for the time-of-day changes in maximal isometric strength
= even though we do see that there is this effect w/ CBT = know that there are generally other factors than just increasing the CT

Question 11

Effectiveness of Resistance Training in the Morning versus Evening Hours (meta-analysis) Grgic et al. [10]

Answer 11

• Similar improvement in strength in both groups, regardless of the time of day of assessments.
• Groups training in AM - strength assessment in AM + PM:
  ○ –> AM training improves strength assessed in AM => training specificity for strength
  ○ No significant dif b/w the strength testing conditions
  ○ –> training effects not transferable to PM
• Group training in PM - strength assessment in AM + PM:
  ○ –> A significant dif b/w testing conditions favouring evening strength assessment
  ○ Training specificity but training effects not transferable to AM

Question 12

A Time for Endurance?

Answer 12

• Some studies have suggested that the adaptations to endurance perf are time-of-day-specific [14, 15].
• Tori et al. [16] found that aerobic training is more effective in the afternoon.
• More than likely to be a temporal specificity to aerobic training for development of endurance perf

Question 13

So Morning OR Evening Exercise?

Answer 13

Evening Exercise
* Greater exercise perf generally occurs
* More favourable anabolic conditions.
* May suit the individual’s sleep chronotype
* If competition/perf assessments will occur at this time of day

Morning Exercise
* Lower fatigue experienced during a session
* Potential for less muscle damage
○ Higher potential for muscle damage in evening = because exercise perf is enhanced in the evening, potentially people push their bodies to a greater extent = therefore lead towards greater damage / loss of substrates etc
* May suit the individual’s sleep chronotype
* If comp/perf assessments will occur at this time of day

Question 14

Overreaching/Overtraining

Answer 14

• Sleep is considered the best strategy to recover from exercise.
• Sleep disturbances are frequently reported as one of the many symptoms of overreaching/ overtraining [17].
• For example, a decrease in sleep efficiency (a measure of sleep quality) in overreached/overtrained compared to non-overreached athletes [18].

Question 15

overreaching + overtraining

Answer 15

• Functional overreaching: short-term reduction in perf that later leads to improved perf after taper/rest.
• Non-functional overreaching: short-term reduction in perf that recovers fully, but does not lead to improved perf after sustained rest.
• Overtraining: longer-term reduction in perf that recovers fully, but only after a sustained period of rest e.g. >2 months.

Question 16

Factors contributing to Inadequate Sleep
1) High Training Load

Answer 16

• Athletes may report difficulties falling asleep, restlessness during sleep, + heavy legs during sleep.
• Innate + adaptive immunity is depressed (e.g., marked reductions in neutrophil function, lymphocyte proliferation + number of circulating T cells) = effected in a negative way
• Associated increased stress + anxiety,+ negative mood may adversely affect sleep

Question 17

Factors contributing to Inadequate Sleep
2) Scheduling of Training + Comp

Answer 17

• Early morning training + comp times have been shown to reduce athletes’ sleep duration + increase pre-training fatigue levels [20, 21].
• In a study of Australian rules football players, evening games were associated w/ later sleep onset time, shorter time in bed, + less total sleep obtained, when compared to day games [22].
• Poorly designed training programs may restrict the opportunity athletes have for sleep, which in turn, may limit recovery b/w training sessions.

Question 18

Dáttilo et al. [23] had subjects perform a “muscle damage” protocol (eccentric contractions) followed by 48 h of total sleep deprivation (DEPRIVATION) or 12 hours of normal sleep.

Answer 18

• No clear difference b/w sleep + deprivation conditions for recovery of muscle strength.
• Eccentric contractions lead towards greater damage than concentric contractions

Question 19

• Higher cortisol/total testosterone ratio for DEPRIVATION compared to SLEEP [23).
• Potential negative affects on muscle adaptations if prolonged?

Answer 19

• Sleep deprivation > 30 hrs (one complete night of no sleep + remaining awake into the afternoon) to impact on anaerobic perf [24].
• Aerobic perf may be decreased after only 24 hrs [25].
• Decrease perf could be due to increased perception of effort

Question 20

Recovery Strategies

Answer 20

• Hydrotherapy: may assist w/ inflammation, immune function, muscle soreness + perception of fatigue.
  ○ Hydrostatic effect of water = that will help w/ the circulation of blood
• Active recovery: may enhanced blood flow, clearance of lactate + other metabolic waste products.
• Stretching: No benefit = in terms of recovery doesn’t really have any effect
  ○ If someone has a tighter muscle = can predispose them to injuries = not a lot of evidence for injury prevention
  ○ If there is an imbalance = important to correct as can lead to injury
  ○ Static stretch can impair perf = cause fatigue
• Compression garments: May reduce swelling, attenuate the inflammatory response + reduce muscle soreness.
• Massage: May assist w/ clearance of metabolic waste products.
• Sleep: Most effective strategy
• Nutrition: Plays an important role in the recovery process + MUST be considered

Question 21

Summary

Answer 21

• There is a range of exercise responses among people.
• Exercise responses may be linked to the timing of exercise + the interaction w/ circadian oscillations in certain genes + hormones.
• Muscle hypertrophy may be enhanced when resistance training is performed in the evening compared to morning.
• Muscle strength + endurance perf does not appear to be affected by time of day BUT there is temporal specificity.
• Overreaching/overtraining negatively affects sleep but also causes problems w/ sleep.
• High training load + scheduling of training/comp is shown to negatively affect sleep.
• Short-term sleep deprivation does not appear to affect muscle strength but seems to diminish endurance perf + increase perception of effort during exercise.
• Recovery strategies should be considered to assist w/ long-term adherence to training programs + achievement of goals