What are the evolutionary roots of West African sprinting and East African distance running dominance?

Thursday, August 18th, 2016

Jon Entine argues that Usain Bolt’s Olympic gold shows again why no Asian, white, or East African will ever be crowned world’s fastest human, but Razib Khan argues that Entine’s wrong — because better drugs and biological engineering mean that the fastest human alive is soon going to be non-African, probably Chinese.

Khan sees running a few seconds faster in the 100 meter dash as a non-adaptively beneficial trait, but Steve Sailer wouldn’t be surprised if the ability to outrun those who are after you and mean to do you harm were an important life skill that is highly adaptive in Darwinian terms:

For example, in 1982, when I had just moved to Chicago, I was headed into the Century Mall on N. Clark St., when a black teen rushed out, followed by two twenty-something Hispanic security guards in close pursuit. I watched them head up Clark Street with the teen in sneakers pulling away from the guards in shiny black leather shoes.

But whether sprinting ability or distance running ability is best for survival depends upon how long pursuers’ sightlines extend in your home terrain.

The shoplifter then turned left at the first corner. It occurred to me that was an important life decision he had just made: if it was a dead end he was in big trouble. But if it were a thru street then he just needed to make a series of seemingly random turns until he had lost his pursuers.

In contrast, if the pursued had headed into open grassland, his pursuers could keep him in sight for a long time, so his better sprinting ability might prove nugatory if they had more endurance.

Perhaps in forested or brush covered terrain, as in West Africa, sprinting is selected for because the pursued individual can get lost faster, while in open grassland, as in East Africa, endurance running is the surest way to get away.

Muscular Human Cannonballs

Friday, August 12th, 2016

Elite female gymnasts are getting smaller, because smaller gymnasts have a better power-to-weight ratio and a lower moment of inertia — but there’s a bit more to it:

In the past, the judges gave taller, more elegantly moving young women advantages because they looked better. But that gave an advantage to Eastern European girls raised in the traditions behind the Bolshoi ballet. The Americans have lobbied to make scoring more objective, which gives the advantages to Mary Lou Retton-style muscular human cannonball body types like Biles’.

41-year-old Oksana Chusovitina

Sunday, August 7th, 2016

“Women’s” gymnastics is famous for its tiny teen athletes, but one Olympic competitor, Oksana Chusovitina, is 41 years old:

When American gymnastics superstar Simone Biles was born in 1997, Oksana Chusovitina had already won five world medals and an Olympic gold.

When Biles’ teammate Laurie Hernandez was born in 2000, Chusovitina was already the mother of a young son.

When Gabby Douglas made her Olympic debut in 2012, Chusovitina was competing in her sixth Games.

A list like this could go on all day, because there might be no other athlete in history who has defied the odds, and Father Time, like the 41-year-old Chusovitina. She is in Rio for her unprecedented seventh Olympics.

Aly Raisman, the U.S. team’s captain, is 22 years old, and she’s returning for her second Olympic Games. Her teammates refer to her as “Grandma Aly” because of her age and habits. And while she may be considered old in the sport, she has quite a ways to go if she wants to match Chusovitina as the oldest woman to ever compete at the Olympics in gymnastics.

Chusovitina was born in 1975 in what is now Uzbekistan, and she learned gymnastics through training in the rigid Soviet Union system. She won the all-around at her first major competition — the USSR’s junior national championships — as a 13-year-old in 1988. In 1991, at her first world championships, she earned three medals, including the gold on floor. To win that title, she mounted with a full-twisting double layout — a move so difficult that it was named after her. It’s still considered so hard that Biles, the favorite to win the 2016 Olympic title on floor, will use the same skill in her first tumbling pass — 25 years later.

She doesn’t train like the young girls:

Due to her age and injury concerns, she isn’t in the gym as much as most of her competitors these days. “At this time, I don’t need much physical training,” she said.

“I do a lot of mental training. I have muscle memory that my body has developed over the years. I typically put in two to two-and-a-half hours in the gym.

“And then I visualize exactly how the skill needs to be done. I do this in my head, and when I get to the gym, all the mental preparation that I did after breakfast or just walking around, it just transfers to the gym and, if I’m vaulting, I know exactly what my body needs to be doing. I know exactly what I need to be doing to get a better execution or a better height or a better landing.”

Presto

Wednesday, August 3rd, 2016

If Penn Jillette looks a bit different now, it may be because — Presto! — he just lost 100 pounds.

He talks to Reason‘s Nick Gillespie about Donald Trump, his crazy diet, and Bob Dylan’s genius:

Ancient and Modern Olympics

Sunday, July 31st, 2016

With the summer games approaching David Stuttard contrasts the ancient and modern Olympics:

While today’s Games stress inclusivity, their ancient counterparts were rigidly exclusive. To compete in this celebration of not just Greek (and, later, Greco-Roman) identity but of proud god-fearing masculinity, you had to speak Greek, be free from the pollution of murder — and be male. Women couldn’t even be spectators. Only the priestess of Demeter could attend.

The chief reason for these restrictions is that the original Games were not really about sport at all. Rather, they were one part of a major male religious festival in honor of the great god Zeus. Indeed, Olympia, site of the Games, was named for Mount Olympus, where Zeus was considered to have had his throne.

I’m not sure sure that the modern games aren’t religious — depending on your definition.

Olympic Vase by Pep Montserrat

The first Games, in 776 B.C., were small-scale and local:

Apart from sacrifices and other religious rites, it included only one sporting event, a footrace of 200 yards, a distance which the Greeks called a stade (hence our “stadium”), and which took well under a minute to run.

[...]

The stade race, run at the midpoint of the Games, remained the centerpiece — so much so that in the fifth-century B.C., when it became desirable to introduce an internationally recognized dating system, the polymath philosopher Hippias hit on the formula, “in the xth year of the yth Olympiad, when z was victor in the footrace.”

The formula caught on, not only promoting the importance of the Games still further but becoming the means whereby a triumphant runner could win everlasting fame.

The words gymnasium and gymnastics come from a time before lycra:

Like other athletes at the Games, runners competed naked. Again, the origins of this tradition were debated, but the most well-known involved Orisippus, a young man from Megara near Athens. Until 720 B.C., loincloths were de rigueur, but that year Orisippus raced so vigorously that his fell off. When he crossed the line to victory, it was seen as a sign from the gods and henceforth any kind of clothing was banned.

But the athletes probably didn’t look exactly naked. By Roman times, if not before, it was common first to anoint the bodies of competitors in oil, then to sprinkle them with dust or powder. One treatise recommended the dust of terra-cotta for helping to open pores, asphalt dust for heating the chilled and yellow earth for softening the skin, commenting that: “Yellow dust also adds glisten, and is a delight to see on a body which is in good shape.” Athletes may well have looked like moving statues.

It was also a time before sunscreen.

There were no team events in the ancient Olympics, by the way.

I find the tone of this passage almost quaint, like something from the pre-UFC 1980s:

The only contact sport forbidden to boys was the pancration, an almost-no-holds-barred free-for-all, in which only biting and eye-gouging were prohibited. A Roman commentator reflected that the competitor must “endure black eyes…and learn holds by which the fallen can still win, and they must be skillful in the various arts of strangulation.”

One pancratist’s win was particularly unconventional. Arrhachion came from Phigalia, a city in mountainous Arcadia. In 564 B.C. the two-time winner came to Olympia where “his opponent, whoever he was, got a grip first and held Arrhachion with his legs squeezed around his neck at the same time. Meanwhile, Arrhachion dislocated a toe on his opponent’s foot but was strangled and expired. At the same time, however, Arrhachion’s opponent gave up because of the pain in his toe. The judges proclaimed Arrhachion the winner and crowned his corpse.”

The ethos has changed most of all:

When Baron de Coubertin revived — or reimagined — the Olympics in 1896, drawing on the ethos of both the ancient Games and English public schools for inspiration, he averred: “What is important in life is not to triumph, but to take part; what is essential is not to have won, but to have fought well.” This may have been a fine late-Victorian ideal, but it was far from the ancient view. At Olympia there were no prizes for coming second, and, fueled by the Homeric exhortation “always to be best,” the desire to win kudos at almost any cost motivated every competitor.

For the aristocratic elite, it was in that most dangerous and exciting of all events, the chariot race, that the most kudos could be earned. Since its introduction in 680 B.C., leading Greek families from Sicily to Libya to the mainland and beyond coveted this prize above all others, because to win it was a sign of immense wealth and good judgment — and, since they hired charioteers to race for them, they ran no physical risks themselves.

Now I’m wondering why there’s no gilded Trump NASCAR car.

Weaker Grips

Thursday, June 23rd, 2016

Researchers from the Winston-Salem State University in North Carolina found that men and women under 30 have weaker grip strength than they did back in 1985:

The researchers asked almost 240 men and women under 30 — most 20 to 24 years old — to exert as much force as they could on a hand dynamometer, which measures grip force in pounds. On average, men’s hand strength decreased by 20 pounds, and women’s hand strength decreased by 10 pounds.

The culprit? Probably a combination of increased technology use at home and at work, and less manual labor. “As a society, we’re no longer agricultural or manufacturing,” Elizabeth Fain, an occupational therapist and lead author of the study, told NPR.

Ten to Twelve Percent Slower

Thursday, June 2nd, 2016

Transgender athlete Joanna Harper explains what happened after her transition:

In 2005, nine months after starting HRT, I was running 12% slower than I had run with male T levels; women run 10-12% slower than men over a wide range of distances. In 2006 I met another trans woman runner and the she had the same experience. I later discovered that, if aging is factored in, this 10-12% loss of speed is standard among trans women endurance athletes. The realization that one can take a male distance runner, make that runner hormonally female, and wind up with a female distance runner of the same relative capability was life changing for me.

Dorian Yates’ First Cycle

Friday, May 20th, 2016

I stumbled across an interview with Dorian Yates — it takes some odd turns, by the way — where he briefly mentions how he started using “gear” right before his first competition — where he blew everyone away:

It was 1985. I was 23 years old and had decided to enter my first competition after a year and a half of training, in which I had made excellent progress. I knew the others who would be competing would be using gear, and I wanted to even the playing field. It was a very deliberate decision that I didn’t take lightly, and I did as much reading as I could first. At 23, I feel I was old enough. At that age, you are fully matured physically, you’ve reached your full adult height, and so on. Even though I hadn’t been training terribly long, I had already managed to develop my physique to a decent level.

Looking back, I may have been able to win that contest without using anything. I did one six-week “building” cycle of 20 milligrams of Dianabol a day, which took me from 215 at 5’11” to 235. Those were the most dramatic results I ever saw from steroids. I took six weeks off the gear, then at eight weeks out from my contest I began using 15 milligrams of Anavar per day, as well as one shot of Primobolan a week, which was 200 milligrams.

I competed at around 210-215 and won that contest. EFBB [Britain’s equivalent of the NPC] officials were there and convinced me to represent the United Kingdom the following weekend as our heavyweight at the IFBB World Games. I placed seventh, and competed with men like Berry de Mey and Matt Mendenhall, both of whom were the top amateur heavyweights in their respective nations at that time.

I suppose Dorian was a natural, even if he wasn’t natural.

One Minute All Out

Wednesday, May 11th, 2016

It still surprises people that one minute of all-out exercise may have all the benefits of 45 minutes of moderate exertion:

[The scientists at McMaster University in Hamilton, Ontario] began by recruiting 25 out-of-shape young men and measuring their current aerobic fitness and, as a marker of general health, their body’s ability to use insulin properly to regulate blood sugar levels. The scientists also biopsied the men’s muscles to examine how well their muscles functioned at a cellular level.

Then the researchers randomly divided the men into three groups. (The scientists plan to study women in subsequent experiments.) One group was asked to change nothing about their current, virtually nonexistent exercise routines; they would be the controls.

A second group began a typical endurance-workout routine, consisting of riding at a moderate pace on a stationary bicycle at the lab for 45 minutes, with a two-minute warm-up and three-minute cool down.

The final group was assigned to interval training, using the most abbreviated workout yet to have shown benefits. Specifically, the volunteers warmed up for two minutes on stationary bicycles, then pedaled as hard as possible for 20 seconds; rode at a very slow pace for two minutes, sprinted all-out again for 20 seconds; recovered with slow riding for another two minutes; pedaled all-out for a final 20 seconds; then cooled down for three minutes. The entire workout lasted 10 minutes, with only one minute of that time being strenuous.

Both groups of exercising volunteers completed three sessions each week for 12 weeks, a period of time that is about twice as long as in most past studies of interval training.

By the end of the study, published in PLOS One, the endurance group had ridden for 27 hours, while the interval group had ridden for six hours, with only 36 minutes of that time being strenuous.

But when the scientists retested the men’s aerobic fitness, muscles and blood-sugar control now, they found that the exercisers showed virtually identical gains, whether they had completed the long endurance workouts or the short, grueling intervals. In both groups, endurance had increased by nearly 20 percent, insulin resistance likewise had improved significantly, and there were significant increases in the number and function of certain microscopic structures in the men’s muscles that are related to energy production and oxygen consumption.

The Sweet Spot for Intermittent Fasting

Wednesday, May 4th, 2016

Mangan shares some research that suggests that the sweet spot for intermittent fasting occurs between 18 and 24 hours:

Fasting Sweet Spot

Understanding and Training the Female Shooter

Monday, May 2nd, 2016

Greg Ellifritz shares some things he learned from Lou Ann Hamblin’s Understanding and Training the Female Shooter class:

When measured on a dynamometer, most men have similar grip strength between their dominant and non-dominant hands (as tested in class, my hands differed by only 2 lbs. of force between right and left). Most women have a HUGE disparity…differences of up to 40% are common. Would that knowledge affect how you teach off-handed shooting for a female student? It should.

Female vision is different than male vision. Women have less depth perception, but better peripheral vision than men. It affects how women see the sights on their guns and how far they have to move their head to do an after-action scan.

Shorter-waisted women have difficulty drawing from many traditional holsters. Their body styles change which gear works best for them.

Women are known to be better multi-taskers than men. This can be problematic in firearms training as some women will try to do too much, taking your suggestions very literally. If you give most women a list of 10 things they are doing “wrong”, they will try to work on them all simultaneously and won’t make as much improvement as if you gave them just one or two things to improve at a time.

Because of differing motivational strategies, competition in training will often yield different results between men and women. Most men really enjoy competition and find it valuable. Because most women are motivated more by social connection than by ego gratification, competition may not give the same benefits. Lou Ann suggested using team competitions (where students are partnered up to achieve a goal) when training women. She believes that women will be better motivated to perform if they are trying to help their partner than if they were trying to win some type of individual award.

“Women need details…but only when they are ready for them. Don’t over-explain things in the beginning, but be ready to explain things in much more detail that you ever imagined necessary when she asks for it. But, she won’t ask for the details if she thinks you are a dick.”

The Sugar Conspiracy

Thursday, April 21st, 2016

The sugar conspiracy seems so brazen in retrospect:

Robert Lustig is a paediatric endocrinologist at the University of California who specialises in the treatment of childhood obesity. A 90-minute talk he gave in 2009, titled Sugar: The Bitter Truth, has now been viewed more than six million times on YouTube. In it, Lustig argues forcefully that fructose, a form of sugar ubiquitous in modern diets, is a “poison” culpable for America’s obesity epidemic.

A year or so before the video was posted, Lustig gave a similar talk to a conference of biochemists in Adelaide, Australia. Afterwards, a scientist in the audience approached him. Surely, the man said, you’ve read Yudkin. Lustig shook his head. John Yudkin, said the scientist, was a British professor of nutrition who had sounded the alarm on sugar back in 1972, in a book called Pure, White, and Deadly.

“If only a small fraction of what we know about the effects of sugar were to be revealed in relation to any other material used as a food additive,” wrote Yudkin, “that material would promptly be banned.” The book did well, but Yudkin paid a high price for it. Prominent nutritionists combined with the food industry to destroy his reputation, and his career never recovered. He died, in 1995, a disappointed, largely forgotten man.

[...]

When Yudkin was conducting his research into the effects of sugar, in the 1960s, a new nutritional orthodoxy was in the process of asserting itself. Its central tenet was that a healthy diet is a low-fat diet. Yudkin led a diminishing band of dissenters who believed that sugar, not fat, was the more likely cause of maladies such as obesity, heart disease and diabetes. But by the time he wrote his book, the commanding heights of the field had been seized by proponents of the fat hypothesis. Yudkin found himself fighting a rearguard action, and he was defeated.

Not just defeated, in fact, but buried. When Lustig returned to California, he searched for Pure, White and Deadly in bookstores and online, to no avail. Eventually, he tracked down a copy after submitting a request to his university library. On reading Yudkin’s introduction, he felt a shock of recognition.

“Holy crap,” Lustig thought. “This guy got there 35 years before me.”

[...]

Look at a graph of postwar obesity rates and it becomes clear that something changed after 1980. In the US, the line rises very gradually until, in the early 1980s, it takes off like an aeroplane. Just 12% of Americans were obese in 1950, 15% in 1980, 35% by 2000. In the UK, the line is flat for decades until the mid-1980s, at which point it also turns towards the sky. Only 6% of Britons were obese in 1980. In the next 20 years that figure more than trebled. Today, two thirds of Britons are either obese or overweight, making this the fattest country in the EU. Type 2 diabetes, closely related to obesity, has risen in tandem in both countries.

At best, we can conclude that the official guidelines did not achieve their objective; at worst, they led to a decades-long health catastrophe.

[...]

We tend to think of heretics as contrarians, individuals with a compulsion to flout conventional wisdom. But sometimes a heretic is simply a mainstream thinker who stays facing the same way while everyone around him turns 180 degrees. When, in 1957, John Yudkin first floated his hypothesis that sugar was a hazard to public health, it was taken seriously, as was its proponent. By the time Yudkin retired, 14 years later, both theory and author had been marginalised and derided. Only now is Yudkin’s work being returned, posthumously, to the scientific mainstream.

Read the whole thing.

Metformin is for fat, sick people

Saturday, January 2nd, 2016

Metformin is for fat, sick people, Mangan concludes:

As is the case with normal lab reference ranges, metformin may help people who are fat and sick, which is almost everyone these days. Two thirds of the people in the U.S. are overweight or obese, most don’t exercise, and they eat processed junk out of boxes and bags. They take lots of prescription drugs.

These people aren’t capable of fighting aging and disease except with a pill.

If you exercise vigorously and regularly (especially strength training), incorporate an intermittent fasting regimen into your health practices, drink coffee, tea, and red wine, take supplements like aspirin and curcumin, and eat a relatively low-carbohydrate diet, is metformin going to increase your lifespan? That seems very doubtful.

If you’re fat, diabetic, and sedentary, and totally unwilling to make any changes in your lifestyle, will metformin help? Probably yes.

The 20 Principles of Rogue Health

Friday, January 1st, 2016

Mangan lists his 20 principles of Rogue Health:

  1. Maintenance of a lean body mass with a relatively low level of body fat is important both for health and for slowing aging.
  2. While having too much fat is bad, having too little muscle may be worse.
  3. We all lose muscle as we age, and most people do nothing about it.
  4. Insulin sensitivity is important for health and aging.
  5. Weightlifting, also known as strength training and resistance training, is the best form of exercise for staying lean, maintaining and growing muscle, combating the frailty of aging, and maintaining good insulin sensitivity.
  6. High intensity training (HIT), is a very effective form of exercise and can be used as an adjunct or, for some, a replacement to weightlifting.
  7. Aerobic exercise, that is exercises such as running, walking, or the use of cardio machines in the gym, have health benefits, but as such they come in a distant second to weightlifting and HIT.
  8. You can’t outrun a bad diet.
  9. If hunger always wins, then to lose fat one must choose a way of eating that dampens hunger.
  10. The cholesterol hypothesis of heart disease is nonsense.
  11. Paleo is a healthy way to eat.
  12. Aging is a multifactorial process, but much of it seems due to a growth-longevity trade-off.
  13. Calorie restriction (CR) robustly extends lifespan in lab animals, but intermittent fasting gives most or all of the benefits of CR without any of its nasty side effects,
  14. Quit eating all the time.
  15. Aging is characterized by a decline in the process of autophagy, the physiological process used by cells to rid themselves of cellular junk and to recycle it.
  16. Hormesis is the process in which a low dose of a toxic compound or stressor elicits a beneficial response from the body, and it is critical to health and anti-aging.
  17. Aging is controlled in part by AMPK, which is a cellular nutrient/energy sensor.
  18. Testosterone is important for men.
  19. Iron can reasonably be suspected as being a primary cause of aging, as well as the cause of the lower life expectancy and higher heart disease and cancer rates versus women.
  20. Stay active.

Ground Combat Element Integrated Task Force

Monday, September 14th, 2015

Some 400 Marines, including about 100 women, signed up to be test subjects in the Marine Corps’ Ground Combat Element Integrated Task Force experiment:

Cpl. Janee’ Sheffield knew she was done when she kept rolling the same ankle on daily hikes, leaving her in constant pain. She dropped on request from the provisional rifle platoon — made up of Marines who had not attended ITB — six days before the unit completed its round of assessments at Twentynine Palms and traveled to nearby Bridgeport for mountain warfare exercises.

Like the other rifle platoons, the provisional platoon was on a repetitive cycle that alternated between two assessment days: a movement-to-contact exercise in which Marines would charge 1,000 yards up a hill with weapons and 30-pound packs, scramble over an 8-foot shipping container and maneuver together toward simulated enemy fire while shooting at pop-up targets; and a hike day involving a roughly 4.5-mile march followed by two arduous hours digging fighting holes.

Before opting out of the task force, Sheffield, 23, had decided the infantry wasn’t for her.

“It sucked; it really sucked,” she said. “I wouldn’t do this experiment again.”

[...]

While videos and photographs released by the Marine Corps show women excelling at combat tasks, Bradshaw said they omitted the moments of failure. He watched a four-woman team struggling for more than seven minutes to move a 200-pound dummy, without success, he said. Another time, he said, female Marines failed to clamber over the top of the shipping container during movement-to-contact assessments.

One lance corporal who entered the experiment “believing that women should get a shot at service in the infantry as long as they could meet existing standards” changed his mind after he saw what happened in the light armored vehicle platoon — where the physical demands weren’t extreme:

Over time, he said, discipline broke down because some noncommissioned officers were hesitant to hurt the feelings of more junior female Marines with orders or correction. Romantic relationships and friendships between male and female unit members also became a distraction, he said.

“The female variable in this social experiment has wrought a fundamental change in the way male NCOs think, act and lead,” Augello wrote in the 13-page paper he presented to Marine leaders, which he shared with Marine Corps Times. “A change that is sadly for the worse, not the better.”

Physically, both the men and women in Augello’s platoon fared well. No one was dropped due to injury over the course of the experiment, unit members said. But the lance corporal said he became frustrated during group assessments, such as an exercise in which platoon members had to work together to haul a dummy weighing nearly 200 pounds out of the vehicle turret and to a designated recovery spot dozens of yards away. When partnered with the platoon’s female Marines, he said he frequently had to compensate for their smaller frames and lack of upper body strength by hauling more of the load.

“I told myself, ‘I don’t know how much longer my back will have after doing this,’” he recalled.

During one assessment, Augello said he found himself paired with the smallest male Marine in the platoon — one who was physically shorter and slighter than a number of the unit’s female Marines. But the Marine’s build and musculature made a significant difference, he said.

“I didn’t feel a lot of stress on my back because he was able to actually help me,” he said. “His upper body strength made the difference at the end of the day.”

The Marine Corps’ data findings included the following:

  • All-male squads and teams outperformed those that included women on 69 percent of the 134 ground combat tasks evaluated.
  • All-male teams were outperformed by mixed-gender teams on two tasks: accuracy in firing the 50-caliber machine gun in traditional rifleman units and the same skill in provisional units. Researchers did not know why gender-mixed teams did better on these skills, but said the advantage did not persist when the teams continued on to movement-under-load exercises.
  • All-male squads in every infantry job were faster than mixed-gender squads in each tactical movement evaluated. The differences between the teams were most pronounced in crew-served weapons teams. Those teams had to carry weapons and ammunition in addition to their individual combat loads.
  • Male-only rifleman squads were more accurate than gender-integrated counterparts on each individual weapons system, including the M4 carbine, the M27 infantry automatic rifle and the M203 grenade launcher.
  • Male Marines with no formal infantry training outperformed infantry-trained women on each weapons system, at levels ranging from 11 to 16 percentage points.

Female Marines often struggled with routine tasks:

In scaling an 8-foot wall obstacle, researchers wrote, male Marines would throw their packs to the top of the wall, while female Marines “required regular assistance” to do the same. During simulated casualty evacuations involving a 200-pound dummy, mixed-gender groups were notably slower at the task, except in cases when a single Marine would move the dummy using a fireman’s carry. And in those cases, “it was most often a male Marine who ‘evacuated’ the casualty,” according to the findings analysis.

Some of the biological data surprised me:

  • The average male Marine volunteer was 178 pounds with 20 percent body fat; the average female volunteer weighed 142 pounds with 24 percent body fat.
  • In anaerobic power and capacity, female Marines averaged 15 percent lower levels than their male counterparts. In anaerobic power performance, the top 25 percent of female performers and the bottom 25 percent of male performers overlapped.
  • In aerobic capacity, female Marines demonstrated levels 10 percent lower on average than male Marines.
  • Over the course of the assessment, musculoskeletal injury rates totaled 40.5 percent for women, more than double the 18.8 percent rate for men.
  • In all, female Marines sustained 21 “time-loss” injuries which took them away from task force duties for a day or more. Nineteen of the women’s injuries were lower extremity injuries and 16 percent took place during a task that required movement while carrying a load. Officials said they could not immediately provide the comparable injury rates for men but said lower extremity injuries were the most common among male Marines as well.

I wouldn’t expect young male Marines to carry 20 percent body-fat.

The real problem is injury rates:

High injury rates among women were also a problem at the Infantry Training Battalion, the Marines’ basic infantry training school for enlisted troops that temporarily opened to women between 2013 and 2015. Researchers found that female ITB participants were injured at more than six times the rate of male participants, and nearly one-third of their injuries occurred during movement-under-load tasks, while just 13 percent of male injuries did.

Overall, women graduated ITB with a 36 percent success rate during the evaluation period. Male Marines had a 99 percent graduation rate during that same window.