electric using a conversion kit like this. switch is a new front wheel with a 250—watt motor in the middle. it also comes with a powerpack and a pedal sensor. this isn't cheap, but it is cheaper than an e—bike, and the price you pay is also your time, which will be dependent on how confident you are with taking off wheels, tires and brake discs. if you think you are going to get stuck then you can pre—book a support video call. obviously i only called them to generate the service, and not because i am a completely clueless dingbat. switch say they will make these kids to fit any size of bike, that basically you discuss with them what you need and they will build the wheel to order. and there is a special adaptor for a folding bike like this one. it is a bit fiddly, but to be honest i did find it perfectly manageable, and that is saying something because it is me.

a tyre and a new wheel. e—bikes use a crank driven system. this is a hub driven system. this magnetic sensor monitors how fast the pedals go around, and then it takes that into account along with things like acceleration to try and work out how much power to deliver. it is not quite as seamless an experience but is a lot cheaper and a lot lighter. but you do have to accept that they will be some extra cables on your frame after this, and a powerpack attached to the handlebars. assuming that won't upset your chi or your aerodynamics too much, you switch it on, select your power assist level and you are ready to go. first pleasant surprise — it wasn't a complete disaster. being a total novice, i did expect it to be harder than it was. secondly, it is outrageously fast. i can't actually have it

on the highest setting, not on the flats — it is just too fast. i hardly touch the pedals and i am away. the only thing is that the power assistance doesn't always behave itself. sometimes cutting out when i need it, and sometimes kicking in when i am not even pedalling. switch say the problem is most likely the pedals and so not being perfectly aligned, and in fact a new design of sensor is going to be available in a few weeks. if you do want to return your bike to a normal, non—electric, you can take the powerpack off, which will leave it only about one kilogram heavier than it was before. although i think that is enough exercise for one lockdown, don't you? wheee! you tested premade e—bikes before — how did this compare? i have to be honest, i know it is the more expensive option but i do prefer the system that looks at how hard you are pedalling

and applies power accordingly, rather than the system which looks at how fast your pedal are going around and having a guess, albeit a good guess, at how much power to apply. the system is cheaper, so, you know, it is your money, take your choice. in the spending may not stop atjust the bike. for lockdown simon hancock put to the test some of the latest cycling gadgets. with public transport, shall we say, not as attractive as it used to be, the bike has become the favoured way for a whole new wave of cyclists to get around time. but be you old—timer orfirst get around time. but be you old—timer or first timer, safety will be a major worry. surprise, surprise, our old friend, technology, has a few gadgets which will help. take this bike liked. it is half light, half radar. it's a really simple idea. you have your phone or your bike computer strapped

to the handles, and as the car approaches behind you, it gives you approaches behind you, it gives you a visual or audio indication that it's doing so. some much needed reassurance or a classic bit of tech overdesign — you decide. it's notjust bike lights that are going smart of course. there are also smart helmets or smart airbags as the hovding likes to describe itself. put it over your head, zip it up and then activate it. and now, as i'm cycling along, if i have an accident and fall off, it will sense that and it will inflate to protect my head. we've had this on the programme a few times before, is the latest generation and comes with an app — of course it does. we'll be able to collect data off the life of everyday cyclists in the tens of thousands of hours and provide that to cities around

the world who are looking for ways to improve the safety of cyclists in their city. cycling accessories getting connected is a big trend and bringing them all online opens up some interesting possibilities. this is the see.sense light — it came out of a kickstarter campaign, and what sets it apart from a standard light is that it's smart. the light uses an accelerometer to monitor the environment up to 800 times a second. the type of data we are bringing into that analysis is things like the condition of the road, the orientation of other cyclists, the cadence, the speed, the breaking. what this means is that the lights do some clever things while you're cycling. on the front light, as you're going around a corner, they seem to flash at a different speed. and with the back light, as you slow down, it acts more like a brake light than a traditional bike light. if you pair the light with a phone,

the user gets some extra features. if you have got one on your bike and you go and get a coffee somewhere and leave your bike outside and someone tries to make off with it, you get an instant alert with your phone, which can be quite useful. in exchange, your cycling data is uploaded to the cloud so see.sense can analyse how people are cycling. one place that has been experimenting with this is the city of london. there are some really interesting examples that have come out of this already. one tells us which bridges people are using, where this data is showing for example, on london bridge compared to southwark bridge, the user experience may be less good because on suffolk bridge there is a better cycling experience in terms of breaking and less swerving which could indicate a propensity for accidents. data helps politicians justify logical decisions because they can show that they are logical and it helps planners make decisions. if you measure where cyclists go now

using see.sense lights or apps or watches, whatever it is they use, they are measuring what they are doing now so you can't go, well, that's where they want to go so i'll build infrastructure that protects people who go there. they might be going there because the place they want to go is a two—lane motorway and they just can't. so a careful interpretation of the data is as critical as gathering it. the humble bike light then has turned bike accessory makers first into tech companies and now into data analysts. all cyclists will care about is that some of this will now genuinely help make the streets of our cities safer to ride. that was simon. it might be that you can't get on a bike where you are, maybe you're just not ready to get out and about yet. but you can still get fit on an exercise bike and lara can help you. the things i do for this programme. i have been doing some high intensity interval training, a spot of hiit. are you into that, spencer? this is when you do

incredibly short bursts of insanely intense exercise. it's horrible. the exercise finishes quicker, though. then you collapse? hopefully not. i've been testing an ai bike called car.o.l that is based on the concept that doing two sets of 20 seconds going at full intensity amidst an 8—minute gentler cycle will give you the benefits of a 45—minute run. no sweating needed. it replicates what is known as laboratory hiit — high intensity interval training — that would usually be carried out in a lab with scientists. they will be able to look at your data and understand your fat—muscle balance, creating a personalised formula and the resistance that you need. here, the ai becomes the scientist. a few setup rides evaluating your physiology

before optimising the workout for you. it's not about how long you spend exercising, it's not about volume. how much you sweat is not linked to effectiveness. the way exercise works is what it does to you at a molecular level. it is hard to keep going as hard as you can for the 20 seconds. as soon as it's over, it's really easy again, and it feels like it was absolutely pathetic. what you're trying to achieve is something called rapid glycogen depletion. and that only happens when you hit your maximum power that you are literally capable of. we will know if you hit super maximum or not based on the amount of time you have held your peak power for. it's impossible to hold it for more than a fraction of a second. i am no scientist so all i can do is tell you how i felt. and even though i am sure my heart rate has been pushed to the right limits,

i was certainly going as hard as i could for those 20 second bursts. but i still didn't feel like i had done a workout afterwards. so each time i did this, i went for a good run after. ok, so this didn't fulfil my workout desires, but there is some science to the 20 second bursts. you only have to look at world athletics records to back up the idea that the body's ability to maintain maximum power deteriorates after the first 20 seconds of pushing to the limit. no matter who you are. the average pace maintained for 100 and 200 metres cannot be continued for sprints that are longer than 20 seconds. so for car.o.l, this means that the user is going to do the bits that they will work the hardest at and get the greatest benefit from, and the rest is pretty easy. even if you only repeated it say,

four to six times, over the course of a couple of weeks, you can see improvements in fitness that are kind of equivalent to what you would get with much longer, typical endurance, continuous training. it tends to have a clearer effect on the heart and circulation system. as an example, this won't help you lose weight. weight loss with exercise about energy expenditure. wow — i have found a whole other side to car.o.l. 60 8—second sprints in 20 minutes and i have never worked out like it. ok, let's do this! speed up — sprint! the only thing that did disappoint me a little bit though was that the ai works based on your last workout rather than in real time. if you're feeling a bit tired, it's not really going to respond to that. i can't deny being pushed to my limits though, and in the longer term, the aim is for the al to be able to react better in the moment,

maybe telling you just by holding onto the handlebars that you're too tired today. i guess we can only hope. do you need much more? we just need a few more shots, lara. can you paddle full pelt again? stop it — i have been working so hard on that bike for weeks! the things you do, like you say. that is it for this week. ifeel like i need a lie down after watching that. you need a lie down? you can keep track on the team throughout the week on facebook, youtube, instagram and twitter at bbc click. thanks for watching, and we will see you soon. buh—bye!

there were plenty of downpours in the uk during friday, but over the weekend there will be far fewer showers. most places will stay dry, and there will be some spells of sunshine. quite a chilly start to saturday morning, but through the day most spots will stay fine with dry spots and sunny spells. one or two patchy showers for north—west england and south—west scotland. even in these areas showers will be the exception rather than the rule. temperatures of 17 to 21, so a touch on the cool side for this time of year. through saturday the rain will move to shetland and orkney. otherwise, dry with clear spells into the first part of sunday. rather chilly first thing, particularly in the countryside, but sunday promises to be another largely fine day with some spells of sunshine. signs of a change into south—western scotland later. some cloud and some rain by the end of

the afternoon. sunday, a warmer day with top temperatures between 19 and 23 degrees.

this is bbc news. welcome if you're watching here in the uk, on pbs in america, or around the globe. i'm james reynolds. our top stories: saved from serving time: president trump commutes the ao—month prison sentence of his longtime ally roger stone. another record jump in coronavirus cases in the united states. we report from arizona, where infections are surging and doctors have to make tough decisions. you have to pick and choose who gets that life—saving intervention, that is a horrible situation to be in, i have never had to be in that situation. amazon says an email asking employees to remove tik tok from their mobile devices was sent in error. and, on the 80th anniversary of the start of the battle of britain, the schoolgirl who helped the raf beat the luftwaffe.