ESPN’s new docuseries “The Last Dance” tells the story of the Chicago Bulls’ historic 6-championship run in the 1990’s. The protagonist, of course, is Michael Jordan.

Aside from giving fans the opportunity to relive the Jordan-era magic, the documentary invites a deeper question — that is, when do athletes peak?

Fortunately, research has some answers. Below are five studies to help you understand the ever-shifting science of athletic longevity, peak performance, and inevitable physical decline.

#1: Professional soccer players are peaking later.

A team of researchers led by Anton Kalen of the University of Vigo in Pontevedra, Spain examined the average age of professional soccer players over the past three decades. They found clear evidence of an upward trend. In 1992, for example, the average player age in the UEFA Champions League was 24.9. Fast forward to today and the average age is closer to 27.

#2: Professional tennis players are peaking later.

Elite tennis players have also been getting older. A 2012 study calculated that the average age of top male tennis players increased at about 0.3 years per season over the past several years, rising from an average age of 26 years to 28 years.

#3: Athletes are getting older across a number of sports.

A recent Wall Street Journal article reported that the average age of Olympic athletes increased from about 25 in 1988 to almost 27 in 2016. “It’s a broad shift that can be seen across the marquee Olympic events,” state the authors of the article, Rachel Bachman and Ben Cohen. “The age of swimmers is up 13%. The age of gymnasts is up 12%. Even the age of athletes in track and field is up 5%. Competitors are also older than ever in canoeing, handball, fencing, judo and table tennis.”

#4: The world’s top chess players are peaking earlier.

While athletes in sports such as soccer, tennis, and Olympic sports are finding ways to successfully extend their careers, there is a countervailing trend at work as well. And this has to do with the rise of young athletes reaching peak performance earlier than ever before. Consider the case of professional chess and the growth of teenage, and even pre-teen, “Grandmasters.” (And let’s save the debate about whether chess is a “true” sport for another time.) In 1950, David Bronstein became the youngest grandmaster of all-time at the age of 26. In 2002, Sergey Karjakin earned that same honor at 12 years, 7 months, and 0 days of age. And Karjakin was no anomaly; his accomplishment was simply the most recent in a series of young chess players pushing the limits of early success.

Incidentally, Magnus Carlsen, the world’s top-rated chess player, is currently hosting an invitational tournament featuring eight of the best chess players in the world, including himself. The average age? 26.6. Keep in mind that chess is a sport that ostensibly requires no physical ability.

#5: The optimal age of e-sports stars may be 24.

A study of Starcraft players published in the journal PloS ONE analyzed massive amounts of data on decision-making and reaction times to see at what age response times begin to slow down. Shockingly, the researchers found that an individual’s cognitive-motor speed begins to decline at 24-years-old. The researchers write, “The effect of age is substantial. For example, a typical Bronze player at the age of 39, equal in all other respects to a 24 year-old adversary, can be expected to be around 150 milliseconds slower in their typical looking-doing latencies, costing about 30 seconds over a typical 15-minute Bronze game containing 200 looking-doing cycles. This is a long time in a game of speed such as StarCraft 2.” 

Conclusion. Returning to the saga of Michael Jordan, he won his last championship with the Bulls at the age of 35, which just so happens to be LeBron James’ current age. While still the best player in the world at that time, he was showing signs of physical decline. “What his body could no longer accomplish in terms of pure physical ability,” wrote David Halberstam in a 1998 New Yorker article, “he could compensate for with his shrewd knowledge of both the game and the opposing players.”

One area of his game that needed no compensation was his competitive spirit. “He wants to cut your heart out and then show it to you,” commented his former coach Doug Collins. It’s likely that Jordan is just as competitive today as he was in the 1990’s.