Certain variables: peak aerobic power (PAP), running economy, and lactate threshold, act as limiting factors for endurance running. However, all of the mechanisms underlying high-level endurance running are not completely clear. Alterations in maximum and explosive strength P27 have been shown to effect positive changes in endurance performance, likely by altering P28 running economy. If strength related factors affect running economy, then this should be evident in the running performance of long-distance runners and perhaps PAP. The purpose of this study was to examine the relationships between peak isometric strength (IPF), explosive strength (rate of force development, RFD), PAP and 3 k performance (3KT) among 5 female and 7 male (n = 12) X-country runners. Force-time curve analysis was conducted for each (2 trials) isometric pull and averaged for analyses. IPF and RFD from 0 - 200 ms were determined from appropriate curves. IPFs were normalized using an allometric (IPFa) scaling equation: absolute force/ (body mass (kg)0.67). ICCs were previously shown to be > 0.9. Relationships were established with Pearson's r; statistical differences with at-Test (p < 0.05). !PF, IPFa and RFD were not different between sexes. PAP was statistically greater in males. Correlations were: PAP vs 3KT (r = -0.92); !PF vs PAP (r = 0.58), 3KT (r = -0.66); IPFa vs PAP (r = 0.45), 3KT (r = 0.45). RFD vs PAP (r = 0.58), 3KT (r = -0.65). Results indicate that strength characteristics correlate moderately to strongly with PAP and 3KT. Data suggests that strong.

Explosive strength, a function of rate of force development (RFD), is a primary determinant for the amount of peak force that can be produced in critical sport performance time periods ( e.g. foot contact time). Evidence indicates that maximum strength and RFD are correlated. However, the characteristics of this relationship are not well established among athletes. This study examined the relationship of peak isometric force (IPF) and RFD from a mid-thigh pull, among male and female track and field athletes. Athletes were 12 sprinters (S), 10 jumpers (JP) and 12 cross-country runners (XC). Force-time curve analysis was conducted for each (2 trials) isometric pull and averaged for analyses. IPF and RFD from 0 - 200 ms were determined from appropriate curves. IPFs were normalized using an allometric (IPFa) scaling equation: absolute force/ (body mass (kg)0.67). ICCs were previously shown to be > 0.9. Relationships were established with Pearson's r; statistical differences with a Bonferroni adjusted t-Test. IPF, IPFa and RFD were greater in males than females for S and JP but not for XC. IPF, IPFa and RFD were greater for S and JP compared to XC. Similar relationships of IPF to RFD were noted among groups S(r = 0.85), JP (r = 0.87), XC (r = 0.88). Among males, n = 19, the relationship ofIPF to RFD was r = 0.89 and was somewhat higher compared to females, n = 15, (r = 0.78). Overall (n = 34) relationship between IPF and RFD was r = 0.90. These data indicate a strong relationship between maximum strength and "explosiveness" that is independent.

Problem: Track and field athletes, along with cross-country athletes have multiple and back to back seasons, creating overuse injuries. Stress fractures or stress reactions to the bone are the overuse injuries focused on in this study and literature review. There is a lack of information in the literature regarding stress reactions. Purpose: The goal of the study is to understand more information about stress reactions to bone and possibly increase the knowledge of health care professionals. Methods: Three case studies were examined through pre-existing medical chart notes and athletic trainer's notes regarding the stress reactions. A literature review was also performed to provide further information about stress fractures and stress reactions. Conclusions: There are multiple risk factors for stress injuries. All three of the athletes in the case studies are female, which is found to be a risk factor. Many risk factors need more studies to provide support. Magnetic Resonance Imaging (MRI) was obtained in all three case studies where there was found to be a stress reaction. These three females also had a recent increase in activity level and had similar symptoms to each other and what is found in the literature.