Fit Cult is going monthly.

A weekly round-up of exercise science research works best when there are lots of studies to choose from but academia runs on its own timeline. So, in an effort to highlight a broader body of work, Fit Cult is changing its publishing schedule. Look out for it on the last Thursday of every month.

The Rundown

Knee/Strength. Want to reduce your risk of symptomatic knee arthritis? Start strength training. A recent study says people with a history of weight training were 23 percent less likely to have arthritis in their knee than those who didn't lift weights. The finding contradicts earlier work based on elite weightlifters showing a high risk of osteoarthritis.

The research looked at 2,607 participants from the Osteoarthritis Initiative, a multi-center study that enrolled people from 2004 to 2006. At their eight-year follow-up visit, the participants completed a questionnaire to determine their exposure to strength training and other activities. Only those who selected strength training as a top three activity were classified as participating in it.

These volunteers had X-rays of their knees taken to determine objective evidence of osteoarthritis, along with an X-ray assessment of recent knee pain, at four-year follow-up visits. To meet the criteria for a diagnosis of symptomatic osteoarthritis, participants were required to have findings in both areas, at least one knee with X-ray evidence of osteoarthritis and frequent knee pain.

Those who engaged in strength training more often had less pain and X-ray evidence of osteoarthritis and those in the highest participation group showed the strongest relationship.

The researchers suggest that weight training might prevent osteoarthritis via improved biomechanics, a reduced risk of injury, better maintenance of weight and improved or preserved mobility.

Rethinking High Lactate Levels. Research out of the University of California, Berkeley is challenging the perception by many athletes and physicians that high lactate levels are bad.

If you’ve ever thought that the buildup of lactic acid was to blame for performance fatigue and muscle soreness after an intense workout, the research team behind the UC Berkeley study offers an alternative way to look at it. They suggest that lactate isn’t a danger sign that athletes have depleted their body’s supply of oxygen. Rather, it’s a normal product of the metabolic activity required to fuel muscles during sustained exercise.

In a paper published in the journal Nature Metabolism, the team showed conclusively that lactate is produced normally in humans after ingestion of carbohydrates. Lactate enters the bloodstream rapidly even before glucose appears. Rather than being a toxic byproduct to be eliminated during hard exercise, dietary glucose is converted so quickly to lactate that it shares the top spot with glucose as the two main carbon-energy carriers in the body.

The results demonstrate that the quick conversion of glucose to lactate, which starts in the intestines, is a way for the body to deal with a sudden dose of carbohydrates. Working with insulin, lactate buffers the appearance of dietary glucose in the blood.

In an earlier study, the authors had shown this to be true during intense exercise. This new research confirms that lactate plays the same role during non-exercise activity and resting.

A co-author explains it this way, “Lactate shouldn’t be associated with oxygen-limited metabolism. It’s just a normal response to consuming carbohydrates or to exercise…It’s not that you’re making it as a waste product. It’s getting into the blood because it needs to go to tissues that need it to continue their physiological performance.”

Extra Point

Watch

30 for 30: Lance. This multi-part documentary series, which originally aired in May 2020, looks back on the life, controversial career and ultimate downfall of the famous cyclist. Lance premieres on Netflix June 3.

Listen

Calm it Down. Composer Chad Lawson started this podcast after fans told him his music helped them feel calm. Each Tuesday, he wants listeners “to learn to pause, breathe and quiet their minds.” Recent episodes talk about letting go of how others see you and making space for what matters most.

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The Fitness Fad Graveyard. Emily Stewart wonders how long Peloton will stick around in this article for Business Insider.