Comments: I used this string before when I did not have wrist and elbow issues and liked it! So I decided to give it another try with my Wilson Clash 100 @ 45lbs, since I have elbow and wrist issues now and also have gotten older. This time, I think that this string is not very soft and lacks power, but definitely adds some crazy actions to the ball. On my other Clash, I have Tecnifibre X-One Biphase 18 which is a more expensive string, but it provides good power and softness for injured wrist and elbow.
From: Mo, Bethesda, Maryland, 9/19/21

Comments: I really like this string. They lasted a full 2 months (approx. 40 sets) before breaking. They have a soft feel and excellent playability. My groundstrokes and serve performed well with these strings. My tennis elbow pain decreased after playing with these strings. I slightly preferred Wilson Sensation 17 over these strings. If the Wilson Sensation strings discontinue, or if my opinion changes, these will be a good string to change to. Enduring ongoing Tennis Elbow about a year ago began my quest to find a new string. I was looking for comfort, playability, good feel, durability, and affordability. I feel a review like this would have been very helpful to me, so I decided to post my findings so perhaps I could help others find their string. I string my own racquets at 59 lbs. All the strings I evaluated were 17 gauge. I play 4-6 hours per week at a 4.5 level. Due to price and durability, my overall #1 choice is Wilson Sensation.
From:Darryl, 2/14

Comments: I have been using IsoSpeed Multi strings for the last year and this string is the best so far. Soft, arm-friendly with nice feel. Not sure about durability yet. I will update later.
From:Todd, 11/13

Comments: I am looking for a new cross string because Solinco has discontinued their Revolution and Tru Feel hybrid. Went with this string because of the arm-friendly reference. Paired with Signum Pro Firestorm in the mains and the playability was really good, but after a couple of hours the ISOSPEED string has already started to fray and doesn't look like they have long left. A really good option if you have good racquet head speed and are looking for a comfortable partner for a poly main, but maybe not the best if you pay for your own re-strings!
From:Charlie, 10/13

Comments: This string really plays like natural gut when it is fresh. It is really soft and spin freandly with superb power and control. However, when I use again after resting for a few days, it feels dead and stiff.
From:Michael, 9/12

Comments: I was curious about this string because it was labeled "plus arm protection", which after shoulder and elbow surgery, I really needed a soft string. And to think I almost didn't try it because of all the negative reviews, but after the first hit, I couldn't believe how softit felt. I am a 5.0 baseliner that plays with a lot of topspin and touch, but the strings didn't move, so I was a bit confused why this was a common complaint with all the other reviewers. It may be because I used the 17 gauge in a 93 frame with an 18X20 pattern. In conclusion, I will continue to use this string because it plays extremely well, and it is very easy on the arm.
From:Robert A, 1/12

Comments: I never played well when hitting with this ISOSPEED string. However, this one is better than the rest of the ISOSPEED strings. It is nothing special, it was moving from the first stroke in my Wilson K Pro Staff 88. I will never buy ISOPSPEED. It is not as soft as Wilson NXT or Tecnifibre X-One Biphase. It is not as crisp or as spin friendly as a co-poly but it is somewhere between.
From:Jan, 8/11

Comments: One of my customers will use nothing but this string. He is a strong 3.5 senior man who uses very little spin. This string is used in the crosses with a more durable string used in the mains. Mains are strung at 52 with the iso speed crosses being strung at 62. It gives him good "pop and feel" his words.
From:Bruce, Abilene, Texas, USA. 07/10

Comments: I've been experimenting with Isospeed for over a year now, trying all their synthetics and even the pyramid poly. I'm currently hitting with a Volkl Tour 10 Midplus (Gen I) with a full, very hard and flat stroke. Being a 4.5 baseline basher, I win most of my points with winners or (paradoxically) drop shots. Most of the time, my main concern is keeping the ball in the court (think of Gael Monfils's 120 mph forehand, but with less spin)... As a result, I place a premium on ball placement, a relatively low level of power, and feel. My wrist injury also demands comfort, and these polyolefin strings are the king of comfort. The Professional (strung at 60#) excels in all these areas, but only for a week or two. Compared to the Classic version, I feel that it loses tension, and thus becomes a trampoline, much more quickly. Durability has been good so far, but since I have little spin, I'm not a string breaker anyway. I would recommend this string to people who are looking for a very arm-friendly, powerful option.
From:Robert, Hayward, CA, USA 10/09

Comments: I will never buy this string again. It only lasted less than 9 hours. Although it is very comfortable and plays well, it doesn't last very long. This string hardly moves and does not develop any notches before it breaks. The breakage starts from the outside where the strings hit the ball, not where the strings rub against each other. The first 3 hours of play I notice the outer layer peeling off. Another 3 hours and the filaments started showing up.
From:Anon. 9/09

Comments: Considering using Isospeed Pro as a cross with natural gut, I decided to try a full job first. Strung it at 52 in a 90. These comments based on this one job... Disappointed straight away by excessive string movement, which was little better than a syngut, despite USRSA rating it 3.5 (well above average) in 'resistance to movement'. Low tension had something to do with this, but... Felt nice, soft and crisp at the same time, if that makes sense. Even at low tension it was low-powered and controllable. But after about 6 hours the outer layer of polypropylene began to fray badly on two crosses. 15 minutes later and that layer looked like it had exploded, with fluffy-looking white hairs puffing out to reveal that the polypropylene layer had ripped in half on those two crosses, revealing a very thin strand of syngut (nylon) in the core. The polypropylene layer then shrank back away from the rupture site as the string lost tension very fast. Surprisingly, the little syngut strands didn't break, but the frame was unplayable at that point, having lost at least 20 pounds of tension on those strings.I don't think this makes a suitable cross string for a hybrid, and will not use it with gut mains. Most strings break in the mains, not the crosses. That this string broke in the cross tells me the outer polypropylene layer isn't up to the job, getting wrecked by the sliding friction of the mains. One of the virtues of the 'Fed setup' is that the gut mains slide freely on the poly crosses - not the case with Isospeed Pro crosses. May as well cross with syngut if you're looking at the Mojo setup, in my opinion. Unless, as some have claimed, Isospeed Pro Classic does a better job in this capacity. But I think a soft poly is probably more suitable.
From:anon. 07/09

Comments: Although I like the feel of this string and the way it plays, it is much softer and wears quicker than the Isospeed Professional Original. If I had to choose between the two, I would stay with the original.
From:Chris, Tacoma, WA, USA, 06/09

Comments: This is the worst string that ever I met! No power, no feel, no comfort, and no spin. Please don't buy this.
From:Daniel, Irvine, CA. 04/09

Comments: Great string with nice feel and power. There is some confusion whether to string this higher or lower than typical, but IsoSpeed recommends that it is strung 10% LOWER with this newer version of the string (higher with the "classic" version). I am able to play about 15 hours or so on a set of strings before changing and the string is also extremely comfortable. I have not had any arm/elbow pain since using IsoSpeed Professional like I did with softer polys. I have not found a string with a better mix of control, feel and power. Great for serve & volley games especially.
From:Todd, Amherst, NY, USA. 6/08

Comments: Well, I first strung my Fischer M Comp with this string. I expected more gut-like feel out of this string like Iso-Speed advertised; however, I did not get it. The string has tremendous control, but my frame doesn't need it. It has enough control of its own. So, if you can bench press 400 pounds for reps, maybe you should get this string. The ball hardly went over the net strung at 45 lbs. As far as feeling like natural gut, forget it. The only string that feels like natural gut is natural gut. The best natural is Babolat.
From:Bear, Pennsylvania. 11/07

Comments: I have been using the original Iso-Speed Professional for about a year in the crosses of my Head MicroGEL Radical (both the pro and regular) with Head Ultratour 17 (poly) in the mains strung relatively tightly. I have continued with this combination and the feel is amazing. The string is ridiculously soft and has very little feedback down into your arm. With the poly, it is very responsive to spin, but the best feature is just the pop off this racquet. Easy power with little feedback makes this string a really good option for those with any arm and elbow problems. However, this just doesn't last. My most recent restring lasted 3 days of a combination of coaching and hitting. It seems that part of what gives it the nice feel is the tight outer layer. It doesn't groove like most strings, and it seems to reach a point where the outer layer just snaps. This leaves a thin fine thread like layer in the middle that won't last more than a game. Again, this string has wonderful feel, and I would highly recommend it to anyone looking for a soft feel with plenty of pop as long as you don't hit with a lot of topspin.
From:Talor, Wollongong, Australia. 11/07