Assisted

Pentoxifylline (PF) has been used to enhance sperm motility in many in vitro fertilization programs. The twofold purpose of this study was to determine whether PF stimulates fresh or frozen epididymal and testicular totally immotile spermatozoa and whether it can be used to select viable spermatozoa for intracytoplasmic sperm injection (ICSI). To test the effect of PF on motility, 10 samples of totally immotile spermatozoa were incubated for 10 min with 3.6 mM PF. Motility was initiated in all cases (14.8% mean motility after PF treatment of five samples of fresh or frozen epididymal spermatozoa and 13.6% mean motility of five samples of fresh or frozen testicular spermatozoa). To assess PF for selection of viable spermatozoa before ICSI, we compared the outcome of ICSI in 20 cycles using fresh or frozen epididymal or testicular PF-treated immotile spermatozoa and 139 control ICSI using fresh or frozen epididymal or testicular spontaneously motile spermatozoa. Fertilization rates we...

Sprint time (ST) is the product of stride length (SL) and stride frequency (SF). Increases in either of these variables results in speed improvement. Purpose:  To compare resisted (RST) and assisted sprint training (AST) on sprint performance. Methods:  Twenty (10 male, 10 female) collegiate sprinters and hurdlers were randomly divided into two training groups: RST (age: 21.81.8yrs, height: 1.730.10m, mass: 69.512.8kg) and AST (age: 22.22.4yrs, height: 1.760.10m, mass: 69.19.9kg). Each group trained 3 days/week for 6 weeks. The RST group used a combination of weighted sled pulls, uphill sprinting and depth jumps. The AST group combined downhill running, towing, sprint ladders and single leg bounds. Prior to and following the training interventions SL and ST (10 meter sprint time) were recorded at sprint distances of 30m, 60m, and 120m during the last 10 meters of each sprint distance. Pre-post training ST and SL were compared within training groups at each sprint distance using paired t-tests. Additionally, a gain score was calculated by taking the difference between the post and pre test scores. The gain scores for SL and ST were compared between training groups via independent t-tests at each sprint distance. Results: For the RST 30m, ST (1.180.08s vs 1.140.08s, p<0.01) and SL (2.060.08m vs. 2.091.14m, p<0.01) were significantly improved. For the AST, 30m ST (1.190.08s vs. 1.180.08s, p<0.01) and SL (2.100.13m vs. 2.110.13, p=0.04) were significantly improved. No improvements in ST or SL were detected for either the RST or AST groups at the 60m sprint distance. For the RST 120m, ST (1.130.07s vs. 1.120.08s, p<0.01) was significantly improved. For the AST 120m, ST (1.120.07s vs. 1.110.07s, p<0.01) and SL (2.300.08 vs. 2.330.08, p<0.01) were significantly improved. At the 30M interval, the RST demonstrated significant improvements in SL and ST as compared to the AST (p<0.01). However, at the 120M interval, the AST demonstrated a significant improvement in SL as compared to the RST (p<0.01). Conclusion: Within the parameters of this study, RST and AST methods have proven effective at improving sprint performance. It appears that RST protocols may be of greatest benefit for improving sprint performance at shorter distances, while AST protocols may be of greater benefit at longer sprinting distances.