[At least] four years of training, thousands of hours of preparation - and then you bomb out of your event at the first attempt.

Spare a thought for Vietnamese lifter Thi Huyen Vuong, who fails in all three attempts to lift a total so she is out.

The competition runs on. Watch here. 

Five-time Olympic swimmerMark Foster has been singing Adam Peaty's praises after he set a world record earlier.

Peaty clocked 57.55 seconds in the 100m breaststroke to break his own world record of 57.98. He goes in the semi-finals after 03:00 BST. 

Foster tells BBC Sport: "His starts have always been a big problem but he looks to have addressed that and no-one is going to get near him. That was frighteningly fast. He has gone a second faster than anyone else in the world and they know they cannot get that time."

Image source, Reuters

Johanna Konta and Heather Watson look to be in a hurry. Perhaps they have a table reserved in one of Rio's trendy churrascarias.

The British pair breeze past Serbia's Jelena Jankovic and Aleksandra Krunic in the women's doubles, needing just 65 minutes to win 6-2 6-1.

Job done.

Image source, Reuters

Venus Williams knows how to find her way onto an Olympic podium, having won four medals in three different Games.

No female tennis player has had a 500g piece of gold, silver or bronze slung around their neck at a fourth Games though.

Can she do it? The Sydney 2000 champion, seeded fifth, wastes four break points in a marathon seventh game in the opening set against Kirsten Flipkens.

Massive hold for the Belgian, who is wearing patriotic - and very snazzy - black, yellow and red specs.

Fancy a bit of basketball? USA are in action against China and lead 44-22 in the second. Kevin Durant is running the show at the moment.

Watch it live here.

Luke Reddy
BBC Sport in Rio

Image source, .

Not a bad venue I think you'll agree. Blue pitch, green edging, yellow ball gives you the colours of Brazil.

Team GB have picked up around £16m in funding from 2013-16. That's a solid investment and so at least one of our teams needs to threaten a medal at least.

The women's team is experienced. Fifteen of the 16 in the squad won the euros in 2015 but Australia are third in the world, four better off than GB.

As for the British side, they live together three weeks of every month to train day in day out.

If you're a trainer geek, Laura Unsworth is your girl, she loves them. Idolise Beyoncé? Well Sam Quek is your pick. Surfing, snowboarding and wild child stuff? Alex Danson.

Proper drama! Hirome Miyake of Japan failed her first two attempts at 81KG, it's Olympics over if she can't lift the third, she gets it up, her knees almost touch the floor but she somehow locks it ou.

Superb. 

The swimming finals start at just after 02:00 BST.

DON'T FADE ON ME NOW.

Steve Bunce
BBC Sport boxing pundit speaking on Radio 5 live

Three British winners in one day at one event. They have boxed well and they will sleep comfortably and kick on in the rest of the week. It has just been a brilliant start for British boxers.

Luke Reddy
BBC Sport in Rio

Image source, Sevens

It's about a 20 minute walk from sevens to hockey but it will be worth it for Great Britain v Australia. 

I've spent time with the British women's side in recent weeks and they collectively told me "Australia only know one way to play". That they say is full on, intensity and robust in all challenges. 

So stay up until 00:30 BST and take it in. The men's side were beaten 4-1 by Belgium earlier. Captain Ashley Jackson said it was "a complete waste of time" and "pretty terrible." I promise you your second instalment of British hockey won't be.

Oh, and on the way over here I ran into the women's sevens side (pictured). No injuries after two wins today, Canada tomorrow the big test in their pool, then onto the quarters.

Our next medal of the night will come in the weightlifting hall, where the final of the women's 48kg is under way.

Competitors have three attempts to lift as much weight as they can in two types of lift: a snatch, where the barbell is lifted above the head in one go, and a clean and jerk, where it is lifted in two movements.

The winner is the athlete with the highest combined total of the two weights lifted.

You can watch here. 

Lawrence Okolie had only had 25 fights before this bout. 25.

Fight number 26 went pretty well to my eyes, and sure enough, he's given the result by all three judges.

Keep your eyes on this lad, he looks like a serious talent.

Low key start to the third, Okolie keeping his distance and working the jab, which makes sense giving he leads on every card.

Jakubowski catches him with a right though, and again! Is the Londoner tiring?

A bit of ring craft needed, see this one out Lawrence, nothing fancy.

There's the bell. Impressive stuff from the young man.

Okolie straight out of the blocks in the second round, causing his opponent to slip - a punch was definitely landed there though.

Jakubowski has a small cut over his left eye as well. His Olympic experience isn't going to plan so far.

Then again, Okolie lets the tempo slip in the second half of that round, a bit of inexperience showing?

Never mind, he takes the round on all three cards once more. 

Michael Tuft: Didn't Olympic boxers used to have to wear head guards? What's happened? #bbcrio2016, external#boxing, external#rio, external

This is the first Games without headguards since 1980 in Moscow. 

See the best video from BBC Sport online now

Image source, BBC Sport