OVERTRAINING: Overtraining Syndrome Symptoms and Diagnosis in Athletes
This systematic review looked at overtraining and current state of knowledge about this syndrome. It's a useful summary of overtraining syndrome (OTS) which is described as "a sports-specific decrease in performance together with disturbances in mood state. Underperformance persists despite a period of recovery lasting weeks or months".
A few notes I took from this review include:
While OTS may be a severe condition that can negatively affect athletes, for practitioners and researchers, there is little data available that describes how physical and psychological qualities manifest. It is our recommendation researchers and practitioners resist the urge to state that OTS has occurred, or infer similar outcomes, when short-term suppression of performance is observed.
As practitioners or researchers would not purposely induce OTS in a group of athletes, it is therefore more likely that individual case studies from prospective cohorts will be the only feasible method of attaining an accurate understanding of the expression of OTS in elite populations.
It should be remembered that the key difference between functional overreaching, nonfunctional overreaching, and OTS is the amount of time needed for performance restoration and/or performance supercompensation. Therefore, the diagnosis of OTS can only be made retrospectively and may be less common than reported throughout the literature.
PRACTICAL TAKEAWAY - it is not easy to diagnose OTS and you should be careful of assuming that an athlete is overtrained when in fact it appears to be relatively less common.
RECOVERY: The week after running a marathon: Effects of running vs elliptical training vs resting on neuromuscular performance and muscle damage recovery
This study set out to test three different post-marathon strategies: "running (RUN), elliptical training (ELIP) and resting recovery (REST). RUN and ELIP groups exercised continuously for 40 min at a moderate intensity (95-105% of the HR corresponding to the first ventilatory threshold) at 48, 96 and 144 h after the marathon". The authors tested for multiple markers including lactate dehydrogenase and creatine kinase as well as testing a squat jump.
The results showed that:
Neither 'Intervention' factor nor 'Intervention x Time' interaction effects were revealed for muscle damage blood markers.
On the other hand, RUN group evidenced an enhancement in SJ performance 96 h post-marathon as compared with REST group.
The authors conclude that:
Return to running at 48 h post-marathon does not seem to have a negative impact on muscle damage recovery up to eight days post-race and it could be recommended in order to speed up neuromuscular recovery.
PRACTICAL TAKEAWAY - returning to exercise soon after a race can be beneficial and does not appear to negatively impact recovery.
I've shared a few papers in the past looking at the physical determinants of trail running performance (here, here, here, and here). This paper investigated runners in three different distances at UTMB to determine what physical factors determined performance: SHORT (OCC ~55km), MEDIUM (CCC ~100km), and LONG (TDS ~145km).
The results showed:
Performance in SHORT was explained by maximal oxygen uptake and lipid utilization at 10 km/h.
Performance in MEDIUM was determined by maximal oxygen uptake, maximal isometric strength, and body fat percentage.
A linear model could not be applied in LONG, but performance was correlated to peak velocity during the incremental test
Performance in trail running is mainly predicted by aerobic capacity, while lipid utilization also influences performance in races less than 60 km and performance in approximately 100 km is influenced by muscle strength and body composition.
PRACTICAL TAKEAWAY - training for different trail distances all require training maximal oxygen uptake, while muscle strength and body composition become more important for medium distance races.
NUTRITION: Effect of dietary nitrate on human muscle power: a systematic review and individual participant data meta-analysis
In this systematic review the authors "undertook a systematic review and individual participant data meta-analysis to quantify the effects of NO3 − supplementation on human muscle power". They found that"
Acute or chronic dietary NO3 − intake significantly increases maximal muscle power in humans.
The magnitude of this effect–on average, ~ 5%–is likely to be of considerable practical and clinical importance.
PRACTICAL TAKEAWAY - supplementing with nitrates appears to be beneficial and is something you should consider.
This study investigated the rate of glycogen usage over three different training sessions, between male and females, and in two different muscles. It has potentially interesting implications for fueling of different training sessions. The authors found:
- prolonged steady-state running necessitates a greater glycogen requirement than shorter but higher-intensity track running sessions.
- female participants display evidence of reduced resting muscle glycogen concentration and net muscle glycogen utilization when compared with male participants.
- net glycogen utilization is higher in the gastrocnemius (G) muscle compared with the vastus lateralis (VL).
PRACTICAL TAKEAWAY - steady state running may require better fueling than shorter, more intense sessions.
RPE is a fantastic measure because it's always available (no running out of batteries or forgetting it at home!), it's subjective, and it's intuitive for most runners. However, it's not without influence and this study set out to test "the effect of peer presence on session rating of perceived exertion (RPE) responses".
The authors found that:
Session-RPE was voted higher when collected in the group’s presence compared with when written.
On average, the posterior probability that session-RPE was higher in the group setting than when written was .53.
The authors conclude that:
Contextual psychosocial inputs influence session-RPE and highlights the importance of session-RPE users controlling the measurement environment when collecting votes.
PRACTICAL TAKEAWAY - be aware of potential factors, such as peer presence, that may influence your RPE assessement of a session.
NUTRITION: Dietary Observations of Ultra-Endurance Runners in Preparation for and During a Continuous 24-h Event
CHO recommendations for endurance sport are well know (up to 90g/hr for events lasting longer than 3hrs). In this study the authors examined the intake of runners in a 24hr event to determine whether they achieved the pre-race nutrition guidelines and the in-race nutrition guidelines. The authors found that:
Pre-race meal CHO intake was within recommended levels (1.5±0.7g·kg−1).
CHO intake over 24–48h pre-race was lower than recommended...in-race CHO intake was only in the 30–60g/h range with suboptimal amounts of multiple transportable CHO consumed.
Strong to moderate positive correlations were observed between distance covered and both CHO and energy intake in each of the three diet periods studied.
PRACTICAL TAKEAWAY - there is room to improve CHO intake in ultra-marathon runners with potential performance benefits. Therefore, find ways or practice nutrition strategies that encourage a higher intake of CHO during a race.
SUPPLEMENT: Effects of creatine supplementation on cognitive function of healthy individuals: A systematic review of randomized controlled trials
The previous research I've shared has outlined the benefits of creatine for recovery, for reducing inflammations, and has addressed some of the misconceptions about creatine. This systematic review set out to investigate "the effects of oral creatine administration on cognitive function in healthy individuals".
Generally, there was evidence that short term memory and intelligence/reasoning may be improved by creatine administration.
Vegetarians responded better than meat-eaters in memory tasks but for other cognitive domains no differences were observed.
PRACTICAL TAKEAWAY - creatine supplementation may be beneficial for cognitive function particularly in vegetarians.
EQUIPMENT: Highly Cushioned Shoes Improve Running Performance in Both the Absence and Presence of Muscle Damage
In this study the authors set out to test the hypotheses that highly cushioned shoes (HCS) "1) improve incremental exercise performance and reduce the oxygen cost (Oc) of submaximal running, and 2) attenuate the deterioration in Oc elicited by muscle damage consequent to a downhill run". From previous research we know that there can be benefits for sacrificing economy for performance and that cushioned and carbon-plated shoes provide benefits on uphill and downhill courses too. There, a better understanding of the benefit of HCS can help us determine when best to use them.
The authors found that:
Incremental treadmill test performance was improved in the HCS when assessed in the nondamaged state, relative to CON. This coincided with a significantly lower Oc at a range of running speeds and an increase in the speed corresponding to 3 mM blood lactate.
In the presence of muscle damage, Oc was significantly lower in HCS compared with CON.
The findings of the present study therefore indicate that HCS may improve maximal incremental running performance and positively influence Oc both in the absence and presence of muscle damage induced by a single downhill run.
PRACTICAL TAKEAWAY - highly cushioned shoes appear to improve running performance particularly with long downhills sections.
An older study (2012) that "aimed to quantify and characterize energy, nutrient, and fluid intakes during endurance competitions and investigate associations with GI symptoms". A broad range of endurance athletes were included in the study that quantified their nutritional intake and GI symptoms during marathons, ironmans, and long distance cycles. The authors found:
Mean CHO intake rates were not significantly different between IM Hawaii, IM GER, and IM 70.3, but lower mean CHO intake rates were reported during CYCLE and MARATHON.
Prevalence of serious GI symptoms was highest during the IM races (∼31%) compared with IM 70.3 (14%), CYCLE (4%), MARATHON (4%), and PRO (7%) and correlated to a history of GI problems.
Total CHO intake rates were positively correlated with nausea and flatulence but were negatively correlated with finishing time during both IM.
PRACTICAL TAKEAWAY - higher intake of CHO (in this case 35-60g/hr) resulted in better performance, however, the higher intake seems to cause more issues when running (during Ironman). Increase your CHO intake along with a gut-training protocol to help improve endurance performance.
This is a single case study so it's hard to make any generalisations and inferences. However, given the limited amount of information available about COVID and recovering from it as an athlete, any additional anecdotal advice is useful to add to your other data points.
In this case study of an elite sprinter, training load "(TL), subjective morning fatigue (MF), and supine HRV were monitored during a 12-week period". The case study notes:
Elevated MF and suboptimal training performance led to a PCR test decision, which returned positive. After a 10-day training suspension, TL was progressively increased with low MF and high vagal tone. The athlete was able to return to competition 17 days after medical clearance for return to participation and 1 week later beat his indoor 60-m personal best.
In this athlete, COVID-19 infection induced parasympathetic hyperactivity with subjective fatigue.
This highlights the importance of TL and HRV monitoring in return-to-participation and return-to-competition decisions.
PRACTICAL TAKEAWAY - carefully monitoring TL and HRV can be useful metrics to inform decisions around possible infections and returning to sport.
I find pacing and tactics in races particularly interesting. Here are a few previous studies I've shared that look at pacing over various distances (1, 2, and 3). This study looked at the "pacing pattern and performance, within sex, and number of crew members, at the very highest performance level in World class rowing". The authors found:
The pacing profiles of the medallists had smaller variation than those of the non-podium finishers.
Compared to the non-podium finishers, the medallists had lower normalized velocities in the first and second segments of the race, slightly higher in the third segment and higher in the fourth segment.
This led to the conclusion that:
Medal winners in major rowing championships use a more even pacing strategy than their final competitors, which could imply that such a strategy is advantageous in rowing.
PRACTICAL TAKEAWAY - a more even pacing strategy is advantageous is rowing races.
This study provides some interesting insights into planning and allocating training. The method of the study was that:
High-intensity interval session-sprint-interval session (HIIT-SIT) completed eight HIIT (8 × 2.5 min intervals; 95% of 2,000 m wattage) followed by eight SIT (three sets of 7 × 30 s intervals; maximum effort). SIT-HIIT completed eight SIT sessions followed by eight HIIT sessions.
The results were that:
Both groups showed similar improvements in 2,000 m time and 4 min “all-out” distance after the first 3 weeks with no significant difference between groups.
The authors conclude that:
Eight sessions of high-intensity training can improve 2,000 m ergometer rowing performance in national-level rowers, with a further eight sessions producing minimal additional improvement. The method of high-intensity training appears less important than the dose.
PRACTICAL TAKEAWAY - planning blocks of high-intensity training may be optimal when 8 sessions are completed. After this period shifting to a different focus stimulus may provide further progress in training adaptations.