Rui Costa

Rui Costa celebrates as he crosses the finish line to win Stage 16 of the Tour de France on Tuesday. (Pascal Guyot / Getty Images / July 16, 2013)

Five things to know as the Tour de France enters its 17th stage Wednesday:

1. Don't mind the gap: Usually at the Tour, the yellow jersey-wearer and his teammates will chase down a breakaway to protect his lead. But during Tuesday's 16th stage, a bunch around Chris Froome didn't pursue more than 20 riders out in front — and by the end, stage winner Rui Costa of Portugal finished a massive 11 minutes 8 seconds ahead of Froome. But the British leader didn't mind the gap: Even with his stage win, the Portuguese rider is in 20th place and remains 22:34 behind Froome.

2. Do mind the bends: Froome got quite a scare during the ride into the Alpine town of Gap. The Team Sky leader was close on the back wheel of third-placed Alberto Contador to repel his repeated attacks, in a dramatic effort by the two-time Tour winner to shake loose even a few seconds from Froome's 4:25 lead over him. Chasing after the Spaniard on the winding final downhill from the Col de Manse — the day's last treachery — Froome skidded off the left side of the road and then planted his left foot on the ground to avoid toppling over completely. Contador also lost his balance and hit his knee on the ground before quickly jumping back up on the bike. The Manse descent was also where Joseba Beloki crashed during the 2003 Tour, breaking a leg, elbow and wrist, and prompting Lance Armstrong to rumble through a small field to avoid hitting the downed Spaniard.

3. The dope-test ritual: "Cadel: Medical!" shouted a BMC team staffer to Australian Cadel Evans just after he crossed the finish last week: It was time to go to doping control. That scene epitomized the daily ritual of drug tests that riders face. The list of cyclists to be tested is posted at a watering station near the finish each day and black-shirted chaperons are ready to escort the crop of riders — at a minimum the stage winner and the wearer of the yellow jersey, usually more — into a doping-control trailer. The French anti-doping agency and cycling's governing body UCI are leading the tests this year — blending both random checks with targeted tests of suspect riders, though they won't indicate which riders fall into either of those categories. No positive tests have been announced.

4. The doctor's note: Sometimes riders can take otherwise banned drugs during the Tour — as long as they have a doctor's note. For example, some cyclists suffer from a type of asthma that is caused by exercise, and can use inhaled medicine to combat it. Some riders have what are known as "therapeutic use exemptions," or TUEs, to be able to use medicine. Critics claim such waivers can open the way for abuse. Kenyan-born Froome has said he's suffered from bilharzia, a tropical disease caused by parasitic worms that live in freshwater snails. He said he last had a check in January, which found it was still in his system. "Every time I find it, I take Biltricide," he said of a medicine commonly used to treat it.

5. Time trial time, part two: The pack splits into its individual parts Wednesday, as riders set off one by one for the 20-mile time trial from Embrun to Chorges in Stage 17. If prior performance is any sign of future results, Froome should shine: He was second in the Tour's first time trial last week and gained more than a minute on all his main rivals hoping to take the yellow jersey off him before Sunday's finish in Paris. The stage features two small climbs in the Alpine foothills.

Stage 16 results

1. Rui Costa, Portugal, Movistar, 3 hours 52 minutes 45 seconds.

2. Christophe Riblon, France, AG2R La Mondiale, 42 seconds behind.

3. Arnold Jeannesson, France, Francaise des Jeux, same time.

4. Jerome Coppel, France, Cofidis, same time.

5. Andreas Kloeden, Germany, RadioShack Leopard, same time.

Overall standings

1. Chris Froome, England, Sky Procycling, 65 hours 15 minutes 36 seconds.

2. Bauke Mollema, Netherlands, Belkin Pro Cycling, 4:14 behind.

3. Alberto Contador, Spain, Team Saxo-Tinkoff, 4:25 behind.

4. Roman Kreuziger, Czech Republic, Team Saxo-Tinkoff, 4:28 behind.

5. Nairo Quintana, Colombia, Movistar, 5:47 behind.