Great article on the similaritie of Floyd's and Manny's rise in the weight class:

Basically, Manny's rise in weight is not unusual and it doesn't neccessarily means he's juicing. Mayweather's Blow Hits Below the Belt 1/10/2010 12:03 AM ET By Kevin Blackistone It's been 17 years since Floyd Mayweather Jr. made his first imprint on the boxing world. It was at the 1993 National Golden Gloves Championships in Little Rock, Ark. He was 16 and won his weight class. Mayweather weighed 106 pounds then. Less than two years later in January 1995, a kid who unbeknownst to any of us then would become Mayweather's most stubborn nemesis, Manny Pacquiao, made a professional debut as a boxer in Occidental Mindoro, Philippines. He was 16 and won a four-round decision against someone named Edmund Enting Ignacio. Pacquiao weighed 106 pounds then. How about that? Mayweather and Pacquiao were both 106-pound, 16-year-old pugilists. But to hear Mayweather's camp tell it -- as led by Mayweather's loquacious father, Floyd Mayweather Sr. -- Mayweather Jr. basically has been a welterweight all of his life while Pacquiao has been hiding in a trainer's room hooked up to an intravenous feed of steroids to inflate his body over the years. If ever there was a case of the pot calling the kettle black, it is Mayweather's camp accusing Pacquiao of being a steroids cheat, a charge that has cast a fight between the two -- something steeped in so much anticipation that it would be the richest prizefight in history -- into a sea of uncertainty. Mayweather's camp, pointing its accusatory finger at Pacquiao, demanded Olympic-style, virtually-up-to-the-last-second blood testing for both combatants. Pacquiao's camp countered that it would agree to blood testing within 14 days of stepping into the ring. Mayweather's camp refused to budge. Now Bob Arum, Pacquiao's promoter, said he is signing up Joshua Clottey as Pacquiao's opponent on the proposed March 13 date for Mayweather-Pacquiao. (This is the same Arum who, it can't be forgotten, said famously once: "Yesterday I was lying; Today I'm telling the truth.") In a lot of ways, this is boxing as usual. One day a fight is on; the next day it is off. Most times the sticking point in negotiations is the share of the purse. Sometimes it is the size of the ring or the gloves. Olympic-style blood testing for steroids is a new stumbling block, and it is understandable. This is the steroids era and stars of the ring haven't proven to be cleaner than stars of any other sports. Shane Mosley got busted as a client of the infamous BALCO business (the Bay Area Laboratory Co-operative) that proved to be a Pandora's Box (spilling out were the world's supposed fastest man Tim Montgomery and his then-lover Marion Jones, baseball All-Stars Jason Giambi and Barry Bonds, et al.) of the steroids era. Evander Holyfield, who grew from a 177-pound light heavyweight to a 221-pound heavyweight champion, admitted he took steroids (unwittingly, of course) around 2004. Accusing someone of cheating, however, is a new and below-the-belt attack. It's not in the same category as name-calling, which Muhammad Ali engaged in. That would explain why Pacquiao filed a defamation lawsuit against Mayweather and his handlers for their thus far unsubstantiated claims that he's been juicing. After all we've learned the past few years, though, no name would surprise me if it popped up on a performance-enhancing drug blotter, neither Pacquiao's nor, for that matter, Mayweather's. Both have grown nine weight classes, from light flyweight to welterweight, and have taken on and beaten Oscar De La Hoya, who has weighed as much as a middleweight, 160 pounds. That is not to say that Mayweather has attained his greatness through the nefarious means he has alleged Pacquiao of getting to at this point in Pacquiao's career. I've never wondered for a second about Mayweather's rise to fame as arguably the best pound-for-pound fighter of his time. I have, however, often wondered why he's made it so difficult at times to make big fights happen. He was dismissive of Antonio Margarito when Margarito would have given him his biggest payday. But I never thought twice about Pacquiao's ascendancy until Mayweather Sr. started calling out Pacquiao the last couple of months and his son didn't voice disagreement. (In the interest of full disclosure, I must state that at one time I was represented by one of Pacquiao's lawyers, Nick Kahn, and accepted a gift of two tickets to Pacquiao's second fight with Erik Morales during my brief hiatus from the regular writing business.) Upon further review, however, I found no more reason to wonder about Pacquiao unless I'm going to start looking at Mayweather with doubt, too. For as history shows, Mayweather has made the exact same climb over nearly the same time period and with results similar to Pacquiao's, though not as spectacular. Mayweather hasn't run roughshod over seemingly bigger men as Pacquiao has, like an aged De La Hoya, who Pacquiao put into retirement, or Miguel Cotto, who Pacquiao turned into mincemeat. Mayweather has put on as much as 44 pounds since he was 16 (he fought De La Hoya at 150 pounds); Pacquiao has put on as much as 38 pounds since he was the same age. Mayweather was up to 131 pounds when he debuted as a pro in October 1996, just over three years after his first Golden Gloves title. Pacquiao didn't get up to 130 pounds until late 2005. Is slow gain not more natural than quick gain? Mayweather has put on the bulk of his added weight -- 19 pounds -- since debuting as a pro. Being from an impoverished region of the Philippines, Pacquiao started boxing for dollars immediately. It doesn't mean much that Pacquiao has never been busted for using banned performance-enhancing drugs. Few athletes own up to as much until they are found out. But that goes for Mayweather too. The only difference between the two is that Mayweather has sounded as if he's chomping at the bit to be tested and Pacquiao has sounded as if he's not so eager. Does that mean Pacquiao has something to hide? Or is Mayweather just calling his bluff? I don't know. All I know is that these two guys are a lot more similar than has been portrayed and the only cheating going on for certain is of the fans.