Katie Downing (Pendleton, Ind../UM-Morris) claimed a silver medal at 149.75 pounds, the top U.S. performance in the women's division at the Canada Cup, held in Calgary, Alberta, Canada, August 5-6.    Downing won three of her four matches during the tournament, and was named the Outstanding Foreign Women's Wrestler of the competition. She was defeated in the gold-medal finals by Canada's Shannon Samler, 5-3. Downing won two matches by technical fall and another by decision.    Three U.S. wrestlers claimed bronze medals: Martiza Collazo at 112.25 pounds, Toccara Montgomery (Cleveland, Ohio/Sunkist Kids) at 149.75 pounds and Dominique Smalley (Colorado Springs, Colo./Dave Schultz WC) at 165.25 pounds.    Smalley, the 2000 Junior World Champion, had a 2-2 record in the tournament. Among her victories was a 4-3 decision over No. 1 ranked U.S. wrestler Iris Smith (Colorado Springs, Colo./Sunkist Kids). Smith had defeated Smalley in four previous matches this season, including the finals of the U.S. Nationals and the Women's World Team Trials.    Smith placed fourth at 165.25 pounds. Another U.S. placewinner was Tina George Wilson (Colorado Springs, Colo./Sunkist Kids), who was fifth at 123.25 pounds.    CANADA CUP at Calgary, Alberta, Canada, August 5-6    Women's medalists    46 kg/101.25 lbs. - Gold - Carol Huynh (Canada); Silver - Angeles Barraza (Mexico); Bronze - Lila Restrevska (Australia)    51 kg/112.25 lbs. - Gold - Lindsay Belisle (Canada); Silver - Magdellena Arellano (Mexico); Bronze - Martiza Collazo (USA)    56 kg/123.25 lbs. - Gold - Erica Sharpe (Canada); Silver - Breanne Graham (Canada); Bronze - Jennifer Ryz (Canada)    62 kg /136.5 lbs. - Gold - Trish Leibel (Canada); Silver - Nicola Hartmann (Austria); Bronze - Lene Aanes (Norway)    68 kg/149.75 lbs. - Gold - Shannon Samler (Canada); Silver - Katie Downing (USA); Bronze - Toccara Montgomery (USA)    75 kg/165.25 lbs. - Gold - Christine Nordhagen-Vierling (Canada); Silver - Nina Englich (Germany); Bronze - Dominique Smalley (USA)    U.S. results    46 kg/101.25 lbs. - Crystal Brown, Colorado Springs, Colo., 5th - lost by tech. fall to Caroly Huynh (Canada), 12-0, 3:21; lost pin to Angeles Barraza (Mexico), 1:27; lost pin to Lila Restrevska (Canada), 1:50; lost dec. to Julie Harris (Canada), 7-3    51 kg/112.25 lbs. - Martiza Collazo, 3rd - lost pin to Lyndsay Belisle (Canada), 1:24    56 kg/123.25 lbs. - Tina George Wilson, Colorado Springs, Colo., 5th - dec. Belinda Chou (Canada), 10-1; dec. Erica Sharpe (Canada), 6-3; lost dec. to Jennifer Ryz (Canada), 7-2    68 kg/149.75 lbs.  - Katie Downing, Pendleton, Ind., 2nd - won by tech. fall over Daniela Leanos (Mexico), 10-0, 2:43; dec. Toccara Montgomery (USA), 7-2; won by tech. fall over Robyn MacDonald (Canada), 14-4, 3:16; lost dec. to Shannon Samler (Canada), 5-3    68 kg/149.75 lbs.  - Toccara Montgomery, Cleveland, Ohio, 3rd - lost by tech. fall to Shannon Samler (Canada), 14-4, 3:49; lost dec. to Katie Downing (USA), 7-2; lost pin Daniela Leanos (Mexico), 0:20; pin Robin MacDonald (Canada), 0:48    75 kg/165.25 lbs. - Dominique Smalley, Colorado Springs, Colo., 3rd - lost by tech. fall to Christine Nordhagen-Vierling (Canada), 11-1; dec. Iris Smith (USA), 4-3; lost by tech. fall to Nina Englich (Germany), 15-2, 4:27; pin Alma Izquierdo (Mexico), 2:01    75 kg/165.25 lbs. - Iris Smith, Colorado Springs, Colo., 4th - lost pin to Christine Nordhagen-Vierling (Canada), 1:35; lost pin to Nina Englich (Germany), 5:45; lost dec. to Dominique Smalley (USA), 4-3; pin Alma Izquierdo (Mexico), 0:28