The advisory for wearing trainers while working out should not be confused with wearing personal trainers while working out, as the latter may cause serious back injuries. Stand strong with today’s Groupon €19.99 for a red neon pro Powerball. This nifty, little red exercise device is the size of a tennis ball and contains an active gyroscope at its core, which, when shaken up, creates bursts of energy through its vigorous rotations. The Powerball fits snugly inside the palm of one’s hand, and as the computer balances flywheel spins and builds up speed internally, it urges holders to grapple against the momentum and resistance is created, helping to tone up wrists and flex arms muscles. The sphere arrives with a digital scoring mechanism and can generate up to 40lbs of resistance and 15,000rpm, which is handy to encourage those that enjoy a little light competition and a bit of casual smugness. The Specifics • Internal gyroscope generates approximately 140lbs of resistance depending on rotor speed • Balanced at speeds in excess of 15,000rpm • Inbuilt speed meter to track high scores • Gyroscope works without motors or batteries • Designed to tone wrists and arms • May help towards gentle rehabilitation for injuries, such as RSI • 25 year guarantee • Lifetime parts replacement More About Powerball This unlikely little exercise ball was first concocted over 12 years ago and has since grown rapidly in popularity. Powerballs are now sold all over the world with thousands of people joining the community and getting involved in friendly competitions by recording their high scores on the World Wide Web. How It Works 1. Buy your Groupon 2. We email you the voucher after the deal ends 3. Voucher activates on Thursday 2 February 2012 at 8pm 4. Go to www.powerballs.com/grouponie 5. In the checkout, enter your voucher codes Groupon vouchers  Shopping  Sports  Sports gear  Sports equipment  Goods Shopping  Sports gear Goods  Sports equipment  Goods Further deals in this category 1. Two Tickets to Any Show and Two Bottles of Beer for €24 at The Laughter Lounge Up to €60 Value 2. Two €129 or Three €159 Night Romantic Getaway For Two With Four Course Meal, Breakfast, and Late CheckOut at Ballina Manor Hotel Up to 65% Off 3. Limited Edition Signed Graham Knuttel Print, in Small €107, Medium €230, or Large €325 4. Two Courses of Indian Fare For Two With Rice or Bread for €24 at Pure Indian Restaurant Rush Up to 56% Off 5. 30 Lap GoKarting For One €9, Two €16, or Four €30 at The Zone Up to 61% Off Further deals in this city 1. ICE Device AllInOne Bluetooth Car Kit €19 Or With Universal Phone Charger Bundle €23 from Bluetooth World Up to 74% Off 2. One €9 or Two €14 Sets Of 360 Stereo Noise Isolating Earphones at Veho Up to 80% Off 3. Six Months of Online Language Courses for €9.99 at Babbel.com 70% Off 4. Ed Hardy Jacket From Choice of Seven Designs for €71 from Born On The Streets 84% Off 5. Austrian Alps Two, Four, or Six Night Stay For Two With Full Board, Car Rental, Spa,  Minibar Vouchers And More from €319 at the Gutshof Zillertal Hotel Up to 70% Off Further deals in Ireland 1. €24 Starter, Main, Side and Drink For Two at the Indian Brasserie Up to €66.85 Value 2. County Sligo Two or Three Night Stay For Two With Breakfast and Late CheckOut from €89 at The Pier Head Hotel Up to 59% Off 3. €22.69 for E200 Electronic Cigarette Starter Kit Plus an ETip Tube with 2 Extra Refills €56.73 Value 4. ’No 1 Mum’ Chocolate Hamper for €19 from Town Country Hampers 50% Off 5. 30 Lap GoKarting For One €9, Two €16, or Four €30 at The Zone Up to 61% Off Further deals in other categories 1. One €13, Two €24, or Three €31 ShamballaStyle CrystalBeaded Bracelets from BoVida Up to 87% Off 2. 26 Page €10, 40 Page €12, or 100 Page €17 Personalised 20x20cm Leather Bound Photobook from Printerpix Up to 80% Off 3. Six Course Package in PC Repair, Maintenance, Networking, Server, Security, and Microsoft Windows 7 Certified by CompTIA for €93 with eCareers.com 92% Off 4. Red Neon Pro NSD Powerball for €19.99 from Powerball 50% Off 5. Koh Samui Stay For Two for €79 Per Night at Code Resort Up to 50% Off