Why Line It Up

Adults stop sprinting. Here is what it costs.

Every number on this page comes from a source you can open. The case for Line It Up is not that sprinting is fun, although it is. It is that speed is the first thing adults lose, almost nobody works to keep it, and a real race is the most reliable way to change that.

What aging does to speed

Power goes first

Muscle does not age evenly. The fast twitch fibers that produce speed and power shrink and disappear before the slow twitch fibers that carry you through a jog. The clock starts in your twenties.

25
the age muscle loss begins

Whole muscle cross sections from men aged 15 to 83 show atrophy starting around 25 and accelerating after that, driven by fiber loss and by shrinkage that hits fast twitch fibers hardest. 10

29%
smaller fast twitch fibers at 71

Healthy 71 year olds had quadriceps 15 percent smaller than 23 year olds, and the entire difference was explained by fast twitch fibers being 29 percent smaller. Six months of resistance training grew them back 24 percent. 11

3.5% a year
leg power lost after 65

In healthy adults aged 65 to 89, leg extensor power fell about 3.5 percent a year, two to three times faster than strength. Power, not strength, predicted how fast people could rise from a chair. 13

Who still sprints

Almost nobody, after school

Sprinting is the most common thing children do on a field and one of the rarest things adults do anywhere. The data on vigorous effort with age is consistent across every country that measures it.

1,158,043
US high schoolers ran track in 2024 to 25

Track and field is the most popular girls sport and the second most popular boys sport in American high schools. 5

0.45%
of English adults do track and field

213,400 adults in England did track and field at least twice in a month in 2023 to 24. Fourteen percent ran. Almost none of them sprinted on a track, and the number is falling. 6

73%
of competitive track athletes are 11 to 19

Of 51,868 people in England with a competitive track and field result in 2018, only 13 percent were 35 or older, and 43 percent of teenagers who competed one year did not compete the next. 7

Sprinting compared with distance running

What a jog does not give you

Distance running is good for you. The evidence for that is enormous and this page does not argue with it. The question is what sprinting adds that steady running does not: the same fitness in a fraction of the time, a stronger effect on blood sugar, and bone that endurance running leaves untouched.

19%
fitness gain, one fifth the time

Twelve weeks of three 20 second all out sprints inside a 10 minute session raised peak oxygen uptake 19 percent in sedentary men, identical to 50 minute moderate sessions, with a five fold smaller time commitment. 18

1.5 hrs
a week, matching 4.5

Six weeks of sprint intervals at about 1.5 hours a week produced the same increases in the muscle machinery for burning carbohydrate and fat as endurance training at 4.5 hours a week and ten times the volume. 19

14%
denser hip bone than non athletes

Master sprinters in their seventies had hip bone density 10 percent higher than master endurance runners and 14 percent higher than people who did not train. The endurance runners were no different from the people who did nothing. 22

The people who kept going

What happens if you never stop

The clearest evidence comes from people who never stopped: masters sprinters followed for a decade with muscle biopsies and bone scans, and sedentary adults in their sixties who started from nothing.

10 years
muscle held, fiber for fiber

Twenty four masters sprinters aged 48 to 85 were biopsied and then biopsied again ten years later. Fiber size and fiber type mix had not changed. They still got slower, 14 percent over 60 m, but the muscle itself held. 25

+17%
peak power, sedentary men at 62

Lifelong sedentary men averaging 62 did one sprint session every five days for six weeks. Peak power rose 124.6 watts, about 17 percent, lean mass rose 2 kg, every participant finished, and no adverse events were recorded. 27

6 sec
sprints, twice a week, at 65

Inactive adults averaging 65 who did six second all out sprints twice a week for eight weeks cut their get up and go time by 1.32 seconds, sit to stand by 2.67 seconds, and two hour blood glucose by 1.32 mmol/L. The control group got worse on glucose and sit to stand. 28

Why a race and not a plan

People show up for a starting line

Everyone knows they should exercise. Knowing has never been the problem. What moves people is a date, a clock, another person on the line, and something to be.

90%
more sessions with competition

In a randomized trial of 790 people, those placed in competitive networks attended 90 percent more exercise classes than those given social support or nothing. The support only group attended fewer than the control. 29

r = 0.44
identity predicts behavior

Across 62 datasets, how strongly a person sees themselves as an athlete correlated with how much they actually move, and the relationship held regardless of study design. 30

+39 min
a week, a year later

New registrants for a weekly timed 5K were still doing 39 more minutes of activity a week 12 months on, ran 12 percent faster, and the overweight among them had lost 2.4 percent of body weight. 32

That is the design. Line It Up is not one race. It is a series with a record that follows you from stop to stop, and a date you can circle before you have decided whether you are a sprinter.

Why the 40

The one number everyone already knows

The 40 yard dash is the most watched footrace in America and almost nobody has run one on a real clock. That gap is the opportunity.

484,000
watched the 40 on a Saturday

NFL Network’s 2025 Combine drew its biggest four day audience since 2017, and the Saturday session with the marquee 40s averaged 484,000 viewers, the network’s best ever for that window. 33

319
people were invited to run it

The official Combine 40 is run by an invitation only group of about 300 draft prospects a year. The record is 4.21 seconds. Only three men have beaten 4.24 since 2008. 34

250M
Americans played something in 2025

A record 250 million Americans took part in a sport, fitness or leisure activity in 2025, and team sports passed 90 million. Yet only 32 percent meet the 150 minute weekly guideline. 35

What Line It Up is doing about it

One race. Four reasons to care.

If you run

A real number, on a real clock, against a real person

You get an officially timed 40 in a bracket, a record that follows you to the next event, and a reason to train for speed that no plan has ever given you. It is free to enter. Officials set the field.

If you watch

Every race is a final

Two people, forty yards, one winner, and the crowd is close enough to hear the start. Nobody hides in a heat. A 52 year old in a final is the best thing you will see all day.

If you sponsor

An audience you cannot buy through media

Everyday adults, 30 to 60, racing on camera in their own city, filmed head to head and put on the record. Sponsorship spend is moving back toward properties like this, and the ones that exist are growing fast. Line It Up is one market today.

If you invest

A new sport with a known number

The 40 is already the most recognized measure of speed in the country. Line It Up is the first place everyday people can run it for real. The format is proven, the first purse has been paid, and the comparables above show what happens when a participation sport finds its format.

Questions from runners, press, partners or investors: info@lineitup40.com

Sources

Where every number comes from

  1. 1Elgaddal N, Kramarow EA (2026). Aerobic Physical Activity Among Adults Age 18 and Older: United States, 2024. NCHS Data Brief 555. National Center for Health Statistics, CDC. cdc.gov/nchs/products/databriefs/db555.htm
  2. 2Elgaddal N, Kramarow EA, Reuben C (2022). Physical Activity Among Adults Aged 18 and Over: United States, 2020. NCHS Data Brief 443. National Center for Health Statistics, CDC. cdc.gov/nchs/products/databriefs/db443.htm
  3. 3Tucker JM, Welk GJ, Beyler NK (2011). Physical activity in U.S. adults: compliance with the Physical Activity Guidelines for Americans. American Journal of Preventive Medicine. pubmed.ncbi.nlm.nih.gov/21406280/
  4. 4Troiano RP, Berrigan D, Dodd KW, Mâsse LC, Tilert T, McDowell M (2008). Physical activity in the United States measured by accelerometer. Medicine & Science in Sports & Exercise. doi.org/10.1249/mss.0b013e31815a51b3
  5. 5National Federation of State High School Associations (2025). Participation in High School Sports Hits Record High with Sizable Increase in 2024-25. NFHS. nfhs.org/stories/participation-in-high-school-sports-hits-record-high-
  6. 6Sport England (2025). Active Lives Adult Survey November 2023-24, Tables 6-8: Types of activity (Table 6a). Sport England official statistics. sportengland.org/research-and-data/data/active-lives
  7. 7England Athletics (2019). Track and Field Participation: Research Summary. England Athletics. d1laub10p5ibfa.cloudfront.net/2019/06/England-Athletics_Track-and-Fiel
  8. 8NPR, Robert Wood Johnson Foundation, Harvard T.H. Chan School of Public Health (2015). Sports and Health in America (n = 2,506 adults). Poll report. media.npr.org/documents/2015/june/sportsandhealthpoll.pdf
  9. 9Pew Research Center (2024). 5 facts about Americans and sports. Pew Research Center. pewresearch.org/short-reads/2024/03/11/5-facts-about-americans-and-spo
  10. 10Lexell J, Taylor CC, Sjöström M (1988). What is the cause of the ageing atrophy? Total number, size and proportion of different fiber types studied in whole vastus lateralis muscle from 15- to 83-year-old men. Journal of the Neurological Sciences. pubmed.ncbi.nlm.nih.gov/3379447/
  11. 11Nilwik R, Snijders T, Leenders M, Groen BB, van Kranenburg J, Verdijk LB, van Loon LJ (2013). The decline in skeletal muscle mass with aging is mainly attributed to a reduction in type II muscle fiber size. Experimental Gerontology. pubmed.ncbi.nlm.nih.gov/23425621/
  12. 12Korhonen MT, Cristea A, Alén M, Häkkinen K, Sipilä S, Mero A, Viitasalo JT, Larsson L, Suominen H (2006). Aging, muscle fiber type, and contractile function in sprint-trained athletes. Journal of Applied Physiology. pubmed.ncbi.nlm.nih.gov/16690791/
  13. 13Skelton DA, Greig CA, Davies JM, Young A (1994). Strength, power and related functional ability of healthy people aged 65-89 years. Age and Ageing. pubmed.ncbi.nlm.nih.gov/7825481/
  14. 14Metter EJ, Conwit R, Tobin J, Fozard JL (1997). Age-associated loss of power and strength in the upper extremities in women and men. Journal of Gerontology: Biological Sciences. pubmed.ncbi.nlm.nih.gov/9310077/
  15. 15McNeil CJ, Doherty TJ, Stashuk DW, Rice CL (2005). Motor unit number estimates in the tibialis anterior muscle of young, old, and very old men. Muscle & Nerve. pubmed.ncbi.nlm.nih.gov/15685623/
  16. 16Korhonen MT, Mero A, Suominen H (2003). Age-related differences in 100-m sprint performance in male and female master runners. Medicine & Science in Sports & Exercise. pubmed.ncbi.nlm.nih.gov/12900699/
  17. 17Rittweger J, di Prampero PE, Maffulli N, Narici MV (2009). Sprint and endurance power and ageing: an analysis of master athletic world records. Proceedings of the Royal Society B. pmc.ncbi.nlm.nih.gov/articles/PMC2660943/
  18. 18Gillen JB, Martin BJ, MacInnis MJ, Skelly LE, Tarnopolsky MA, Gibala MJ (2016). Twelve Weeks of Sprint Interval Training Improves Indices of Cardiometabolic Health Similar to Traditional Endurance Training despite a Five-Fold Lower Exercise Volume and Time Commitment. PLOS ONE. journals.plos.org/plosone/article?id=10.1371/journal.pone.0154075
  19. 19Burgomaster KA, Howarth KR, Phillips SM, Rakobowchuk M, Macdonald MJ, McGee SL, Gibala MJ (2008). Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans. The Journal of Physiology. pubmed.ncbi.nlm.nih.gov/17991697/
  20. 20Vollaard NBJ, Metcalfe RS, Williams S (2017). Effect of Number of Sprints in an SIT Session on Change in VO2max: A Meta-analysis. Medicine & Science in Sports & Exercise. doi.org/10.1249/MSS.0000000000001204
  21. 21Jelleyman C, Yates T, O’Donovan G, Gray LJ, King JA, Khunti K, Davies MJ (2015). The effects of high-intensity interval training on glucose regulation and insulin resistance: a meta-analysis. Obesity Reviews. pubmed.ncbi.nlm.nih.gov/26481101/
  22. 22Piasecki J, McPhee JS, Hannam K, Deere KC, Elhakeem A, Piasecki M, Degens H, Tobias JH, Ireland A (2018). Hip and spine bone mineral density are greater in master sprinters, but not endurance runners compared with non-athletic controls. Archives of Osteoporosis. pmc.ncbi.nlm.nih.gov/articles/PMC6028830/
  23. 23Stamatakis E, Ahmadi MN, Gill JMR, Thøgersen-Ntoumani C, Gibala MJ, Doherty A, Hamer M (2022). Association of wearable device-measured vigorous intermittent lifestyle physical activity with mortality. Nature Medicine. pubmed.ncbi.nlm.nih.gov/36482104/
  24. 24Lee DC, Pate RR, Lavie CJ, Sui X, Church TS, Blair SN (2014). Leisure-time running reduces all-cause and cardiovascular mortality risk. Journal of the American College of Cardiology. pubmed.ncbi.nlm.nih.gov/25082581/
  25. 25Hendrickse PW, Hutz B, Korhonen MT, Degens H (2025). A 10-Year Longitudinal Study of Muscle Morphology and Performance in Masters Sprinters. Journal of Cachexia, Sarcopenia and Muscle. pmc.ncbi.nlm.nih.gov/articles/PMC12034575/
  26. 26Suominen TH, Alén M, Törmäkangas T, Piasecki J, Kekäläinen J, Ireland A, Korhonen MT (2021). Regular Strength and Sprint Training Counteracts Bone Aging: A 10-Year Follow-Up in Male Masters Athletes. JBMR Plus. pmc.ncbi.nlm.nih.gov/articles/PMC8260815/
  27. 27Sculthorpe NF, Herbert P, Grace F (2017). One session of high-intensity interval training (HIIT) every 5 days, improves muscle power but not static balance in lifelong sedentary ageing men: A randomized controlled trial. Medicine (Baltimore). pmc.ncbi.nlm.nih.gov/articles/PMC5313002/
  28. 28Adamson S, Kavaliauskas M, Lorimer R, Babraj J (2020). The Impact of Sprint Interval Training Frequency on Blood Glucose Control and Physical Function of Older Adults. International Journal of Environmental Research and Public Health. pmc.ncbi.nlm.nih.gov/articles/PMC7013863/
  29. 29Zhang J, Brackbill D, Yang S, Becker J, Herbert N, Centola D (2016). Support or competition? How online social networks increase physical activity: A randomized controlled trial. Preventive Medicine Reports. pmc.ncbi.nlm.nih.gov/articles/PMC5008041/
  30. 30Rhodes RE, Kaushal N, Quinlan A (2016). Is physical activity a part of who I am? A review and meta-analysis of identity, schema and physical activity. Health Psychology Review. doi.org/10.1080/17437199.2016.1143334
  31. 31McVinnie Z, Plateau CR, Lane A, Murphy N, Stevinson C (2023). Effects of engaging in mass participation sporting events on physical activity behaviour: a systematic review. Health Promotion International. academic.oup.com/heapro/article/38/2/daad018/7084728
  32. 32Stevinson C, Hickson M (2019). Changes in physical activity, weight and wellbeing outcomes among attendees of a weekly mass participation event: a prospective 12-month study. Journal of Public Health. academic.oup.com/jpubhealth/article-abstract/41/4/807/5123524
  33. 33Florio M (2025). NFL Network sees highest Scouting Combine viewership since 2017. NBC Sports, Pro Football Talk. nbcsports.com/nfl/profootballtalk/rumor-mill/news/nfl-network-sees-hig
  34. 34Edholm E (2026). 2026 NFL combine: Who will run the fastest 40-yard dash? 21 contenders to know. NFL.com. nfl.com/news/2026-nfl-combine-who-will-run-the-fastest-40-yard-dash-21
  35. 35Sports & Fitness Industry Association (2026). 2026 Topline Participation Report. SFIA. sfia.org/resources/participation-hits-new-high-but-majority-of-america
  36. 36Two Circles (2025). 250B Reasons Why Brands Are Backing Sports. Two Circles. twocircles.com/us/articles/250b-reasons-why-brands-are-backing-sports-
  37. 37Sim J (2026). How Hyrox is turning fitness into the world’s next mass participation sport. SportsPro. sportspro.com/features/finance-investment/hyrox-business-model-mass-pa
  38. 38Donaldson A (Sportcal); Kings League press release (2026). Investment firm Alignment Growth leads $63m Kings League funding round; Kings League announces $63 million investment round. Sportcal; PR Newswire. sportcal.com/news/investment-firm-alignment-growth-leads-63m-kings-lea
  39. 39Islam A (SportsPro); Cohen A (Front Office Sports) (2025). Major League Pickleball team valued at US$10m following AZ Drive sale; Major League Pickleball team values skyrocket to $10 million. SportsPro; Front Office Sports. sportspro.com/news/major-league-pickleball-team-sale-az-drive-value-mi