Kuhlman, Nicholas M.

Introduction Female distance runners are at elevated risk for impaired bone remodeling due to high mechanical loading, potential low energy availability, and sustained inflammatory stress. Collagen peptide (CP) supplementation has been proposed as a nutritional strategy to support type I collagen synthesis and modulate osteoimmune signaling; however, evidence in premenopausal endurance athletes is limited. This pilot randomized, double-blind, placebo-controlled trial examined the effects of four weeks of high-dose CP supplementation on markers of bone metabolism and inflammatory activity in endurance-trained premenopausal women. Methods Twenty-two participants (18–35 years; ≥35 miles/week [>56km/week]) were randomized to CP (INT; 20 g/day) or isocaloric maltodextrin (CON). Pre- and post-intervention assessments, conducted in the early follicular phase, included serum procollagen type I N-terminal propeptide (P1NP), plasma C-terminal telopeptide of type I collagen (CTX-1), serum soluble receptor activator of nuclear factor-κB ligand (sRANKL), osteoprotegerin (OPG), the sRANKL/OPG ratio, and interleukin-6 (IL-6). Repeated-measures ANCOVAs were performed, adjusting for accumulated running distance and vitamin D status. Results A significant group × time interaction was observed for P1NP ( p = 0.04), with increases in INT and no change in CON. No significant interaction was observed for CTX-1 ( p = 0.13). Significant interactions were also observed for sRANKL ( p = 0.046) and IL-6 ( p = 0.03). No significant interaction effects were detected for sRANKL, OPG, or the sRANKL/OPG ratio. Discussion Short-term CP supplementation increased a marker of bone formation, altered osteoclast-related signaling, and reduced IL-6 in endurance-trained premenopausal women. These findings support the potential for CP-mediated modulation of bone turnover and inflammatory activity and warrant further investigation in larger, adequately powered trials incorporating structural bone outcomes.

Objective: To evaluate the current literature on the role of collagen peptide supplementation in bone health, focusing on changes in bone turnover markers (BTMs) and bone mineral density (BMD). Data Sources: A search was conducted following PRISMA guidelines in the databases Academic Search Premier, APA PsychInfo, CINAHL Plus, GreenFILE, MEDLINE, and SPORTDiscus. Keywords included “collagen supplementation,” “bone turnover,” and “bone structure.” Studies published between January 2000 and March 2024 were included if they involved human subjects, oral collagen supplementation, and skeletal-related outcomes (BTMs or BMD). Risk of bias was assessed using the modified Physiotherapy Evidence Database (PEDro) scale. Main Results: Fifteen studies met the inclusion criteria. Collagen supplementation was associated with improvements in BTMs such as procollagen type I N-terminal propeptide and C-terminal telopeptide of type I collagen, as well as increases in BMD at whole body, femoral neck, and lumbar spine sites, particularly in postmenopausal women. However, neutral findings and substantial heterogeneity in study design, population characteristics, and dosing protocols were also observed. Conclusions: Collagen supplementation shows promise for supporting bone health, particularly in postmenopausal women, but the evidence remains inconsistent. Future research should address these gaps by focusing on premenopausal populations, standardizing dosing protocols, and exploring broader orthopedic applications, such as reducing stress fractures and enhancing recovery from musculoskeletal injuries.

Abstract Kuhlman, NM, Jagim, AR, Jones, MT, Feit, MK, and Fields, JB. A comparison of match external load demands across women’s collegiate field sports. J Strength Cond Res 39(2): 234–241, 2025—Historically, soccer (SOC), lacrosse (LAX), and field hockey (FH) have been grouped together as “field sports” due to their intermittent nature of match play and similar physiological demands. However, questions have emerged regarding potential variations in demands between sports. The purpose of this study was to compare external match workloads between collegiate women's SOC, LAX, and FH, and examine within-sport positional differences. Athletes (SOC: n = 15; LAX: n = 15; FH: n = 14) wore a global positioning system device during all matches throughout a competitive season. External load metrics included in the analysis were total distance (TD), sprint distance (SD), accelerations (>3 m·s −2 ), sprint efforts (SE), player load (PL), PL per minute (PL/min), top speed (m·s −1 ), and distances covered in select speed zones. Soccer performed higher external load volumes (TD, PL) ( p ≤ 0.025) but incurred lower intensities (SD, SE, accelerations) ( p < 0.001) compared with LAX and FH. Within-sport positional differences were apparent in SOC ( p < 0.001–0.018), LAX ( p < 0.001–0.045), and FH ( p < 0.001–0.004). However, FH exhibited more positional variance in external load metrics compared with SOC or LAX. Field hockey midfielders covered greater volumes (TD, PL) compared with attackers and defenders ( p < 0.001), while attackers sustained greater intensities (SD, SE, top speed) compared with midfielders and defenders ( p < 0.004). Results indicate that there are significant differences in external workload parameters between sports and across positions. Practitioners should tailor sport-specific and position-specific programs to match demands, and future research should explore the proposed categorizations of LAX as a “fast collision invasion sport,” FH as a “fast contact invasion sport,” and SOC as a “slow contact invasion sport.”

Abstract Fields, JB, Kuhlman, NM, Jagim, AR, Dulak-Sigler, C, and Jones, MT. Analysis of accumulated workloads and performance testing across a collegiate women's lacrosse season. J Strength Cond Res 37(11): 2213–2221, 2023—Monitoring accumulated workloads, acute:chronic workload ratios (ACWR), and training monotony (TM) are practical methods for monitoring athlete physical stress. Performance testing provides useful information about the changing nature of physical abilities. Therefore, the purpose was to examine differences in accumulated workloads based on session type, explore seasonal trends in ACWR and TM, and assess changes in performance assessments in collegiate women's lacrosse athletes. Athletes, who were identified as starters ( n = 12), wore positional monitoring technology during training sessions ( n = 61) and games ( n = 17) and completed preseason and postseason assessments of speed, agility, power (jump tests), strength, aerobic capacity, and body composition. Separate 1-way analyses of variance were used to determine differences in accumulated workloads for session type and differences in performance assessments from preseason to postseason ( p < 0.05). When compared with games, practice sessions elicited greater ( p < 0.001) accumulated total distance, player load, repeated high-intensity efforts, accelerations, change of direction, explosive efforts, high-speed efforts ( p = 0.002), and high-speed distance ( p = 0.002). Throughout the season, ACWR and TM ranged from 0.16 to 1.40 AU and 0.68–1.69 AU, respectively. The 40-yd sprint ( p < 0.001) and pro-agility ( p < 0.001) improved from preseason to postseason, whereas no changes in aerobic capacity, lower-body power, or strength were observed ( p > 0.05). The monitoring of accumulated loads, ACWR and TM, and performance tests revealed novel information about the seasonal demands of collegiate women's lacrosse. Women lacrosse players are able to improve speed and agility throughout the season, while maintaining strength, power, and endurance, with minimal reductions in fat-free mass.