Starting area
BIB number

After 460 days not wearing a bib number for an “official” competition, we were back on a starting line. We travelled to Mafra, in Portugal, for the Linhas de Torres Running Challenge, an athletic event organized among others by the Portuguese Army, and with modalities of 100k individual or by teams, 42k on foot or on horseback and 10k.

Obviously, we opted for the marathon distance, for a demanding trail course with 1600 meters D+ (and another 1300 meters of descent). The route going from Mafra to Torres Vedras follow the lines of Portuguese defensive forts built to face the Napoleonic invasions of the 19th century.

With just over a hundred participants, and the start on one side of the Mafra National Palace, declared a World Heritage Site, you cannot ask for a better return to the competition. In addition, the meteorological forecast accompanies, with a predicted temperature of 18⁰C and clouds, instead of the high 20⁰C on previous days.

In Portugal they love trails, and races of this type are always demanding. In a semi-autonomous regime, there are only 4 supply points on the route. That means carrying a backpack, although used to it, is not a big deal.

Shortly after the start, I meet once again an old acquaintance from my times in the UK, Tiago Dionisio, an avid marathoner, and ultra-runner, with more than 700 to his credit. However, knowing what lies ahead, each keeps his own pace.

The route is mostly through wooded areas, in which the rugged terrain forces you to look where putting your feet to avoid falls. With continuous ups and downs, it is a constant leg breaker. I try to maintain my running cadence on the ascents, although the steep descents slowing down are also punishing to the quadriceps.

One of the few road sections

The second refreshment station is at the highest point of the route. In the 23.4 kilometres, at the top of the Hermitage of Nossa Senhora do Socorro, there are bifanas, soup, bananas, energy bars and nuts available. I stop briefly to have some fruit and refill the backpack. The next checkpoint is 13 kilometres away.

Although the next 2 or 3 kilometres are downhill, the climbs are not over yet. With the legs already tired, I take a breath and start walking up the hardest slopes. I see possible to finish under 5 hours.

Arriving at the last checkpoint in the 36.3k I have been running for 4h15m and Torres Vedras can be seen in the distance. In a “road” marathon at these stages the worst is over. Here, though, there is still much to go, and new trails follow one after another.

Finally, I cross the finish line with 5.27.22 for one of the toughest marathons I have come across, second only to the Trionium Picnic in the UK. My second worst time ever in the Pheidippides distance, although happy to return to official competitions on a highly demanding course.

With the calendar shyly opening, we can start making some competition plans. Hopefully, we have already passed the worst of this pandemic.

On horse marathon participant
Getting a rest at the finish line


Photo by Quino Al (Unsplash)

Running, as sports in general, is associated with many benefits for prevention and rehabilitation of health issues, although it also carries an injury risk.

Among the risk factors for running, we could highlight training load, anatomical and biomechanical (footwear) variables, lifestyle (drinking & smoking), health status (injuries history) and sex.

Sex has been linked to specific injuries and for overall injury risk. Using data from 14 international athletics championships a previous study showed that male athletes had lower incidence of bone stress injuries than females.

 A recent systematic review of the literature on sex-related injuries found 38 studies eligible, including a total of over 35000 runners (40.8% females – 59.2% males), including road, track, cross-country and trail/orienteering runners (from recreational to elite level). The main findings follow.

Overall Injury Rates

  • No difference in overall injury rates between male and female runners (around 20 injuries per 100 runners).
  • In distances longer than 10 kilometres: higher injury risk in male runners.
  • In distances shorter than 10 kilometres: higher injury risk in female runners.


Bone Stress Injuries

  • Higher probability in female runners.

A possible explanation is their association with the female athlete triad:

              low energy availability + menstrual dysfunction + low bone mineral density

Although similar symptoms have also been described in male athletes, mainly due to what is called relative energy deficiency.


Achilles Tendinopathy

  • Higher probability (twice the risk) in male runners.

The Achilles tendon is key for propulsion during running but its poor blood supply makes it prone to overuse injuries (tendinopathies). The difference between this injury rates in males and females could be explained by hormonal differences.

Oestrogens, whose levels are high in women, are associated with collagen synthesis, and therefore with tendon healing capacity. Hormonal fluctuations during the menstrual cycle have not been associated with modifications of tendon function.


  • Sex is not a risk factor when considering the overall occurrence of injuries in running.
  • Female runners sustain more frequently bone stress injuries.
  • Male runners have higher risk of developing Achilles’ tendinopathies.
  • Prevention, treatment, and rehabilitation strategies would be more effective when considering sex of the individual.


What is your personal experience about injuries?



Sex-Specific Differences in Running Injuries: A Systematic Review with Meta-Analysis and Meta-Regression. Hollander, K., Rahlf, A.L., Wilke, J. et al. Sports Med (2021).


Photo by Pasja100 (Pixabay)

The pacing strategy alternating periods of walking and running is known as the Galloway Method, after Jeff Galloway, the former US Olympic runner who popularized it. According to his theory, walk breaks help to endure fatigue and reduce or eliminate muscle breakdown.

Worth to mention that this run-walk method is not used only when the athlete is tired, but throughout the whole race. By reducing overall impact on the body, it has allowed many runners, especially beginners, to go farther, and even faster, than they would have achieved simply by running.

According to the runner level and strategy the running:walking intervals may differ greatly, going from an easier 1:1 ratio to a more demanding 8:1, when the runner would run 8 continuous minutes and then walk during 1.

Despite the Galloway Method popularity, a question remains:

Does a runner need more energy when changing speeds or while running at a constant pace?


The study

A recent study has used a treadmill and a group of recreational runners who did the following:

  • 6 min continuous running
  • 6 min continuous walking
  • 12 min alternating 2-min periods of run and walk

Being measured the energy expenditure per kilometre (kcal/km), the distance traversed per litre of absolute oxygen (m/L O2) and the rate of perceived exertion (RPE) for each of the conditions.



  • Energy expenditure

Walking consumed less energy (9 kcal) for a given distance than running, although when alternating every two minutes participants required 4 kcal extra to traverse one kilometre than running it. For a marathon race it would mean 168 kcal more.

  • Distance traversed

Walking allowed participants to traverse 12.31 metres farther per litre of oxygen consumed than while running. There was no difference when between participants running or using the Galloway method.

  • Fatigue

There was only a small reduction in perceived exertion for the runners when using the run-walk method than with continuous running.


  • Alternating periods of running and walking did not save any energy per kilometre when compared to continuous running and only offered a slight reduction of perceived fatigue.
  • On the positive side, the Galloway method can reduce the risks of injury and allow a better management of fatigue, pain, and discomfort in marathons, although limiting the performance.



Run-walk marathon pacing: the energy cost of frequent walk breaks. William P. Nolan & Andrew R. Moore (2021), International Journal of Performance Analysis in Sport, 21:1, 170-179, DOI: 10.1080/24748668.2020.1862493

Photo by Drew Farwel (Unsplash)

ESGUEVA MARATHON (23/04/2021 – 96)

Picking up the torch from Quique´s marathon two weeks ago, it is time to organize a new one. The chosen date, Friday April 23, festivity of Castilla y Léon, and incidentally commemorating the fifth centenary of the “Comuneros” defeat in the Battle of Villalar.

The circuit will follow the riverbank of the Esgueva as it leaves Valladolid, a linear and flat route of just over 7 kilometres that will have to be run 6 times to complete the distance of Pheidippides.

At the start, once again the usual ones: Quique, Lola and David, both going for their fourth marathon on as many weekends, and Kacho opting for half the distance. Pepe is going to miss it.

Being festive only at regional level does not help travel, but with four for the marathon, we are enough to “validate” it, a criterion that will still give a lot to talk about.

During the week forecast had been promising water, although later it changed, and finally the morning appears only with some clouds and good temperature.

After two weeks of active rest, trying to recover physically (and psychologically) from the last event, it seems that things can go better today. Thus, and although not perfect of “sensations”, at least I can manage to run the first 2 laps with the others.

Shortly afterwards David pulls forward and we let him go. I still make it to the half marathon with Quique, who has been holding back so as not to get me off the hook. By that point I still have a small margin to get below 4 hours.

Later in the day we must overcome quite a few walkers and cyclists, something that I did not have foreseen, as I usually have trained on this path much earlier and during weekdays.

Meanwhile, the race continues its course. I keep Quique and Lola at a visual distance, while David is already quite far. Running back for the last time and seeing that the 4 hours are going to escape me again, I squeeze what is left in me.

In the end I cross the finish line at 4.04.28, improving almost 20 minutes the debacle of 13 days ago, although again above the 4 hours finish time. On the positive side, a marathon less to reach the 100-barrier…

After the fifth MIV marathon, during the post-race talk, we begin to glimpse the light at the end of the tunnel for the “official” competitions. Among others, the names of the marathons of Gran Canaria, San Sebastián, Reykjavik, Tokyo and even the North Pole ring out …

It is what the marathon has that, like sports in general, knows no borders, and will survive to Covid, even if it is based on PCRs or “clandestine” marathons.


Photo by Massimo Sartirana (Pixabay)

According to the American College of Sports Medicine up to 50% of athletes use nutritional supplements. Among the most popular supplements nowadays are antioxidants, used to improve performance and fight against Exercise-Induced Muscle Damage (EIMD) and fatigue.

Two of the most popular antioxidants are vitamin C and vitamin E, capable of neutralising the reactive oxygen species (ROS) derived from intense exercise. Despite their extensive use most athletes consume adequate levels daily (Vitamin C: 75 mg/day females – 90 mg/day males; Vitamin E: 15 mg/day) in the diet through fruits, vegetables, and nuts, among other sources.

Some authors suggest that the transient rise of ROS with exercise is beneficial. Thus, antioxidant supplementation could impair athletes training adaptations, instead of helping them.

A recent review has investigated the effects of vitamin E and C supplementation on exercise performance. Their main findings are described below.

Vitamin C

  • Muscle strength and function are not affected.
  • Individuals with vitamin C deficiency increase exercise performance with supplementation.

Vitamin E

  • Effects on endurance are confuse.
  • During high intensity intervals acute supplementation improves performance (less oxidative stress and faster recovery).
  • Chronic supplementation may impair training adaptations and future exercise performance.


  • Chronic supplementation with vitamin E (with or without vitamin C) impairs athletic performance and is not currently recommended for athletes (except for those training at high altitude).
  • Acute antioxidant supplementation improves performance in high intensity/short recovery intervals exercise, conditions where an IMMEDIATE enhancement of performance is pursued.
  • To ensure antioxidants needs athletes should focus on consuming a diet high in them (fruits, vegetables, nuts…) instead of using supplements.
  • Determining the oxidative state of athletes would allow personalized supplementation.



Antioxidants and Exercise Performance: With a Focus on Vitamin E and C Supplementation. Higgins MR, Izadi A, Kaviani M. Int J Environ Res Public Health. 2020 Nov 15; 17(22):8452. doi: 10.3390/ijerph17228452.

Antioxidants rich foods


Staring group (lacking Pepe)

We returned to the distance of 42 kilometers in the vicinity of Valladolid. Quique organized in the pine forest of his village, Tudela de Duero, the next “clandestine” marathon of the Independent Marathons of Valladolid MIV.

Given the circumstances, we are 6 runners for the marathon, and 3 for the half-marathon distance. Among the marathoners, familiar faces such as Pepe, Quique and I from the locals, Lola and David from the Madrid side, and Joserra from Galicia as a new addition.

The morning dawned with good temperature, although with a forecast of rain, to do 14 laps of a circuit through the pine forest around the Santinos recreational area.

The last two weeks had been the chronicle of an announced failure. No day had I ever found myself fresh. I don’t know if the February and March “loads” were excessive, or the recovery time was insufficient.

I started running calm and lagged the leading group a bit. There are many laps and I have them in sight. I can close the gap whenever I want (I think).

Santinos pine forest

However, already in the second lap I feel that the legs do not accompany, and the feeling will only get worse as the race goes on. At the end of the fifth lap it starts to rain heavily, and some puddles appear on the sandy ground, but without causing much discomfort.

In the middle of the race, and with another 7 laps to go, the mind has a lot of work to do. The ghost of a DNF flies over my head, although the pleasant journey through the pine forest makes up for the effort.

The distance of Pheidippides always commands respect, and sometimes demands a toll, bringing out the best in us. You must forget the stopwatch and focus on finishing. I still remember marathons like the Lemmings track or the one in Funchal, and they are not enjoyed the same… It is feeling your body dissociated: going well at core level, but the legs not responding.

Running the penultimate lap, Quique and Lola get to double me. But my marathon is another one, and already within reach…

I cross the finish line with 4.23.57, a time that leaves me unsatisfied, although it serves to add the 95 to my personal count.

We will return, hopefully with better feelings.

Some time into the race (before the rain)


Photo by Quino AI (Unsplash)

During the 1990s some studies calculated that women would overtake men performance in the marathon event, because of their steeper increase in running velocity over the years.

Despite these studies, other models defended that there would always prevail a 10% difference advantage of males over females in running performance, due to their greater aerobic capacity (VO2max). This was confirmed by studying more than 90000 non-elite marathoners, where males had finishing times around 10% faster than females (4h28m vs. 4h54m).

But let´s talk about ultra-endurance sports, whose popularity has increased a lot in recent years. In these events, success is determined by a whole set of factors. We could highlight oxidative capacity, running energy cost, fatigue and pain resistance, nutrition, gastrointestinal system, experience, strategy, and motivation, among a few others.

Any runner needs a good set of skills to compete successfully in an ultra-marathon, but also be able to endure high training volumes and push their physiological limits to the edge.

On the marathon distance male/female ratios are around 50%, with males running a 10% faster than females, as we have mentioned previously. In ultra-endurance events though, female participants are often in higher numbers than males.

In these long events, the difference in finishing times between males and females goes down to 4% in ultra-marathons, 6% in ultra-distance open water swimming and is absent in cycling events longer than 200 miles.

Do these numbers mean that females are more physiologically prepared to endure the hardest of the events? Or these lower differences may be due to greater participation and training opportunities nowadays?

A recent article has reviewed the factors that could explain this potential advantage.

Photo by Quino AI (Unsplash)


Fibres in human skeletal muscles can be type-I/slow or type-II/fast.

Type-I fibres are more resistant to fatigue, accounting in a study for 44% of the total fibres in females and only 36% in males. Additionally, they are associated with higher levels of capillarization and blood flow to the muscles.

Regarding muscle mass, males are more muscular, due to a greater diameter of the muscle fibres and not because of a higher number of them. Stronger muscles can restrict blood flow and lead to muscle fatigue earlier during isometric submaximal exercise.

Both factors would favour females having a greater resistance to fatigue than males.

Regarding the respiratory muscles, though, it seems that females are in disadvantage. Due to lung size, diameter of airways and the utilization of a greater percentage of VO2 during effort they could have lower oxygen economy during exercise.


Substrate utilization

Oxidative metabolism is essential in ultra-endurance exercise. The longer the distance the more intense is the use of free fatty acids.

Females show greater expression of genes associated with the metabolism of fatty acids, as it is the CD36, associated with a 4-fold increase of fatty acids metabolism in a mice model.

Thus, females could have a metabolic advantage during long duration exercise. Better efficiency would reduce caloric requirements and the need of exogenous carbohydrates.


Oxygen use

Aerobic metabolism is limited by the maximal oxygen uptake. Superior performance in males is associated with higher VO2max values, trained or untrained.

Although the lower VO2max would certainly be a disadvantage for females in races of any distance up to the marathon, there are other factors influencing the performance in ultra-marathon events.

Thus, females have usually more conservative running strategies, explaining why they often are capable to maintain pace better than males. They take decisions to mitigate muscle damage and fatigue, key limiting factors of performance.


Gastrointestinal disorders

The most common disturbances in sports are nausea/vomiting and abdominal cramps, with a higher prevalence in females.

Despite this, due to better substrate efficiency, lower body mass and lower caloric needs females don´t need to consume as many carbohydrates as males. This is of special relevance because carbohydrates intake is the main cause of gastrointestinal disorders.

Thus, although female athletes may be more prone to gastrointestinal disorders, their lower caloric needs may compensate for these disturbances.



  • Female athletes exhibit various characteristics that can confer them an advantage in ultra-endurance sports: a greater percentage of type-I fibres, greater fatigue-resistance, better substrate efficiency, lower energetic requirements and even be better at pacing.
  • But some physiological characteristics can counteract these advantages, such O2 carrying capacity, gastrointestinal disorders and hormonal effects on cellular function and injury risk.
  • Considering the pros and cons of the factors mentioned above, the current article concludes that the fastest females will never outperform the fastest males, except in ultra-distance swimming.



Do Sex Differences in Physiology Confer a Female Advantage in Ultra-Endurance Sport? Tiller, N.B., Elliott-Sale, K.J., Knechtle, B. et al. Sports Med (2021).

Photo by Jasmin Sessler


Mizuki Noguchi winning the 2004 Olympic marathon

“I want to keep running until my legs break down for good.”

Mizuki Noguchi

The 2004 Summer Olympics saw the Olympic Games go back where they began. Athens was chosen as the host city leading all the voting rounds, defeating Rome, Cape Town, Stockholm, and Buenos Aires. That would be the second time that Athens would hold the Olympics after the inaugural ones of modern times in 1896.

Regarding the marathon, it would follow the same route than the 1896 Olympics. Starting on the site of the Battle of Marathon it would finish in the Panathenaic Stadium of Athens. And it wasn´t an easy course, with many hills until the final ten kilometres, that were mainly downhill.

The women´s marathon was going to take place on August 22 at 18.00. Considering Greek´s summer weather it was going to be a tough race. For starters the evening offered a 30% humidity and 35°C!

Let´s see first how the women´s marathon scene was at that time…

The main favourite was the British Paula Radcliffe, who had dominated the marathon distance since her debut in London 2002 with 2.18.55, the second fastest time ever. Later that year she won Chicago with a WR of 2.17.47, a time she further improved in London 2003 to 2.15.25. But 2004 had been a tough year for her, with various injuries complicating her training schedule.

Besides Radcliffe, the Kenyan Catherine Ndereba was second in the rankings and World Champion. And here was, as usual, a powerful Japanese team with Mizuki Noguchi and  Naoko Sakamoto, who had been second and fourth in the World Championships of Saint-Denis in 2003, and the strong Romanian Lidia Simon, already silver in Sydney 2000.

Noguchi started running short distances in school, before transitioning to cross-country events, where she won the gold medal in the Asian Championships of 1999. That same year she won the Inuyama half marathon, and focused on this event, where she would manage to win 14 out of 24 half-marathons. She tried for the first time the full marathon distance in 2002 in Nagoya, where she won in 2.25.35. The following year she won the Osaka women only marathon in 2.21.18, finishing second in the World Championships (2.24.14).

But it is time to get back to the 2004 Olympics marathon, where 82 runners were starting the race.

Radcliffe took the lead of the race from the start, with a group of runners tagging along. They crossed the 10k in 34.25 and the 20k in 1.09.57. None of them were playing their cards, but everything was about to change.

Passing the 25k there was an uphill section, where Radcliffe struggled to keep her pace. That seemed as an opportunity to Noguchi, who increased her pace and took the lead. Crossing the 30k (1.45.02) she was leading 28s ahead of Elfenesh Alemu, from Ethiopia. Shortly behind them were coming Radcliffe and Ndereba.

Near the 35k Radcliffe launched a desperate attack searching for the medals. It was futile. Overtaken by Ndereba, and temporarily out of the medal positions, she stopped on the side of the road. Sobbing, and lost all hope, she abandoned the race.

Meanwhile Ndereba was closing the gap with Noguchi. In the 40k (2.19.00) her lead was down to just 12s. The next two runners were much further: Alemu at 1.17 and the United States’ athlete Deena Kastor, at 1.35, strongly chasing the bronze medal.

Entering the Panathinaiko Stadium Noguchi kept her lead, winning Ndereba by 12s and a second consecutive gold medal for Japan in the event with 2.26.20. The bronze medal went surprisingly to Kastor in 2.27.20, who had run the second half of the race 4 minutes faster than the first!

From the 82 starters, only 66 finished the race.

Noguchi´s victories weren´t over. She won the Berlin Marathon of 2005 with 2.19.12, establishing the course record, but also the Japanese and Asian ones. She didn´t go to the Olympics of Beijing 2008 due to physical problems and missed also the following two seasons. In 2012 she failed to qualify for London 2012. A talented runner she run many other races in a range of distances before retiring in 2016.

Regarding Ndereba, she would add another two Boston Marathon victories to her previous two ones and would have another shot to Olympic glory in Beijing 2008, similarly to Kastor, but…

It will be told in a future post.

Thanks for reading!



Athens 2004 Olympics opening ceremony


Photo by Jane Sundried (Unsplash)

The therapy

HBOT is medical treatment that involves breathing pure oxygen in a pressurized chamber (ambient pressure higher than atmospheric pressure).


A brief story

  • 1662: British physician Nathaniel Henshaw builds a pressurized room to treat pulmonary and digestive conditions.
  • 1788: hyperbaric air in a diving bell is used for underwater repairs.
  • 1819: first deep-sea diving suit.
  • 1834: French doctor Junod builds the first hyperbaric tank to treat a variety of medical conditions.
  • 1900s: Frech doctors discover that patients with surgery in hyperbaric conditions recovered with fewer complictations.
  • 1907: JS Haldane designs decompression chamber to treat decompression sickness in divers.
  • 1918: Dr. Orville Cunningham discovers a difference in flu´s mortality rate among patients living at high altitude, leading to many patients to seek HBOT treatments.
  • 1963: JFK´s child, Patrick Bouvier, is treated from Respiratory Distress Syndrome in a HBOT chamber, although he dies aged 2 days.
Individual hyperbaric chamber

How does it work?

  • On wound healing: damaged blood vessels release fluids that cause swelling in the tissues, depriving them of oxygen. HBOT helps healing by providing tissues with plasma rich in oxygen. Additionally, it helps to remove the harmful free radicals.
  • On immune system: HBOT improves the ability of white blood cells to fight against infectious diseases and foreign invaders. It also blocks the action of many harmful bacteria.
  • On aging: telomeres are the end parts of the chromosomes and their shortening is linked to aging. Elongating theses telomeres is associated with a longer life, and although exercise and a healthy diet have been shown to have small effects on them, HBOT is said to reverse aging. Patients that received oxygen therapy sessions daily over 3 months showed longer telomeres and a smaller number of senescent cells than control individuals.
  • On sports recovery: HBOT induces the formation of new collagen fibres, present in muscles, tendons, ligaments, cartilage, or skin, among others.


The chambers for HBOT can be monoplace, where the patient slips into the chamber, or multiplace, designed as a room where various persons simultaneously breath through masks.

Sessions, lasting up to 2 hours, should be provided only in healthcare or approved facilities, and is not recommended in people with ear problems, cold, fever or some lung diseases.

Although an expensive therapy, its use is becoming more common. Among the famous sportsmen using HBOT therapy we can find Rafael Nadal, Cristiano Ronaldo or Lebron James. But does HBOT also improve performance? Its effects are unclear yet.

Did you have any experience with hyperbaric oxygen therapy? We would like to read your comments.



John Scott Haldane: The father of oxygen therapy. Sekhar KC, Rao SC. Indian J Anaesth 2014; 58:350-2.

Multiplace hyperbaric chamber


It was clear from how things were going that the easiest way to run a marathon was to organize one. After overcoming in December the fear of doing something for the first time, it seemed the ideal moment for another marathon from the runner/organizer perspective.

Taking advantage of a gap in the calendar, since the Madrid Command is going with everything, we opted to concentrate efforts on a single day, Sunday, March 7. And again the chosen site was Zaratán, but instead of the last route, opting for a friendlier one: the Vía Verde of the Tren Burra (Donkey Train). Like the missed Vías Verdes marathons, we would use a reconditioned old railway, in this case the one that made the Valladolid-Medina de Rioseco route until 1969.

On a 6.55 kilometres course, 1 short lap and 6 full laps would be necessary to complete the marathon distance. Of course, once again to show that Valladolid is not as flat as it seems, it was a demanding marathon, with a smoothly ascent in the way out, but difficult after repeating it several times.

In the end we were only 5 runners at the start: Pepe, Quique, Lola, David and me, who have already shared a few marathons. With a punctual start at 9.00 it is a perfect day to race, improving the weather forecast. It was just a matter of completing the race in the best possible time, especially not knowing when we will be able to have another chance to run a marathon.

Although during the first 2 laps we ran close to each other, we end up running alone, except for Quique and Lola, who escape in front, although I manage to keep them in sight. Facing the last lap I am counting on maybe reaching them. However they are strong and I have no chance.

I enter slightly above the 4-hours barrier, at 4.03.19, thus completing the marathon number 94, first of 2021 and first on a day 7.

All gathered at the finish line, new marathons begin to be shuffled: that is one of the dangers of the marathon family. But the most important bit is that everyone has a place in it, from the lone wolves to the marathon hunters.

Meanwhile we will continue looking for courses and experiences.