This study involved a 28-week school-based exercise trial of single-leg drop-landing exercise with 42 girls (Tanner stage 1; 6-10 yr old) randomly assigned to control (C), low-drop (LD) or high-drop(HD) exercise groups. The latter two groups performed single-leg drop-landings (3 sessions.wk-1 and 50 landings.session-1) from 14cm and 28cm, respectively using the non-dominant leg. Single-leg peak ground-reaction impact forces (PGRIF) in a sub-sample ranged between 2.5 – 4.4 x body-weight (BW). No differences (p>0.05) among groups at baseline for age, stature, lean tissue mass (LTM - DXA - Lunar 3.6-DPX), leisure time physical activity or average daily calcium intake were detected. No significant within group changes for between leg differences from baseline to post-training and no significant differences among groups at baseline, or in magnitude of change for any of the dominant or non-dominant (loaded) leg bone mineral content (BMC g) measures determined by DXA – loaded leg total - 19.06, 25.5, 25.46 [p=.156], femoral neck - 0.14, 0.11, 0.15 [p=.959], greater trochanter - 0.37, 0.06, 0.26 [p=.733], mid femoral shaft - 3.87, 3.87, 3.42 [p=.677] for the C, LD and HD groups, respectively, after adjusting for the covariates baseline body and fat mass, and change in LTM (ANCOVA) were observed. Similarly, following ANCOVA adjustments no significant differences for changes in calcaneal speed of sound and broadband ultrasound attenuation (CUBA Clinical), DXA derived changes in femoral neck (-0.009, 0.033, -0.009; p=.189) and total MFS (0.029, 0.041, 0.053; p=.447) volumetric BMD (g.cm-3), or MFS cortical volumetric BMD, the latter derived by a new technique combining MRI and DXA were identified. TBBMC changed by 79.6g-C, 100.2g-LD and 91.9g-HD (p=.339). Combining data from both exercise groups to increase statistical power produced similar results. No significant within group changes for between leg differences from baseline to post-training and no significant differences among groups at baseline, or in magnitude of change for any of the dominant or non-dominant (loaded) leg bone geometrical (area cm2) determined by MRI using ANALYZE® software of proximal - 22.18, 12.91, 19.86 [p=.248], mid - 19.83, 15.91, 19.64 [p=.233], or distal - 14.78, 16.07, 13.35 [p=.792], slice cortical area for the C, LD and HD groups, respectively, after adjusting for the covariates baseline body and fat mass, and change in LTM (ANCOVA) were detected. Similarly there were no significant biomechanical cross sectional moment of inertia (CSMI cm4) changes determined by Scion Image® (Frederick, Maryland: Version-Beta 3B) and a custom macro program of proximal - 896, 815, 649 [p=.415], mid - 1054, 806, 1087 [p=.471], or distal - 1197, 1079, 966 [p=.606], slice CSMI for the C, LD and HD groups, respectively after adjusting for the same covariates. In contrast to some recent reports, our findings suggest that strictly controlled uni-modal; uni-directional single-leg drop-landing exercises involving low-moderate peak ground-reaction impact forces are not osteogenic in the developing prepubertal female skeleton.

Infertility among women has become a growing issue in the world requiring a significant number of women to seek treatment by means of assisted reproductive technologies (ART). One suggested reason for the fertility issue is modern diet, leading to diseases such as obesity and type II diabetes. In this study, twenty gilts three weeks in age, were placed on one of five dietary treatments (n=4 gilts per treatment) containing 15% fat (FAT), 35% fructose (FRU), both fat and fructose (HFHF), or two different controls: one standard industry (IND) diet meant to result in optimal lean growth and a second diet to account for the reduced lysine (LYS) intake in the treatment diets. Two experiments were performed to assess the reproductive outcomes of pre-pubertal gilts consuming a high fat and/or high fructose diet and to demonstrate interactions between diet and infertility using pigs as a model. In the first experiment, follicular fluid was collected from these gilts and introduced into porcine in vitro maturation system to determine whether characteristics of the follicular fluid affect oocyte competence and embryo development. The follicular fluid of females consuming high fructose and fat diets did not alter nuclear maturation of oocytes (p>0.10). There were, however, detrimental effects on subsequent development of embryos, especially blastocyst formation, with the gilts having consumed the HFHF diet having reduced day 5 and 6 blastocysts formation when compared to the IVM follicular fluid free (FFF) group (p=0.03 and p=0.01, respectively). In regards to embryo quality, blastocysts from the FAT group had greater cell number when compared to all other groups. In the second experiment, the reproductive tissues; ovary, oviduct, and uterus were analyzed for genes of interest: estrogen receptor alpha (ESR1), estrogen receptor beta (ESR2), insulin like growth factor I (IGFI), insulin like growth factor I receptor (IGFIR), and growth differentiation factor 9 (GDF9). Resulting data was analyzed in three ways: 1) across all 5 treatments, 2) with gilts grouped by whether or not they consumed fat, or 3) with gilts grouped by whether or not they consumed fructose. There were no differences detected between individual treatments for ESR1 and ESR2. In the ovary samples, the fructose diets decreases ESR2 (p=0.05). Also, GDF9 ovarian expression tended to decrease with fructose consumption (p=0.07). Furthermore in the ovary, there was a positive correlation between ESR2 and GDF9 expression (r=0.92 and p<0.01). GDF9 expression was lower in the oviducts of gilts consuming fat diets when compared to non-fat diets (p=0.01). Neither IGFI nor IGFIR were altered in the reproductive tissues analyzed. Based on the results from both experiments, the consumption of fat and fructose alters both the developing embryo and gene expression in the reproductive tissues that support the growing embryo. Further investigation will provide more insight on the impact nutrition has on pre-pubertal reproductive development and subsequent fertility. / Master of Science

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