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To describe concussion characteristics among general college students and compare postinjury outcomes to intercollegiate student athletes.Retrospective cohort.Large university in the Southeast region of the United States.A total of 179 (N=179) college students' (female=120; 67.0%; 23.9±3.9 years) and 49 athletes' (female=28, 57.1%;19.3±1.3 years) medical records were examined. Participants self-reported injury mechanism, health history information, and completed clinical assessments acutely (7 days postinjury).Descriptive statistics were calculated for each group. Concussion outcomes between students with and without certain health history diagnoses were assessed using separate t tests. We conducted univariate regression analyses to determine if sex, age, and time from concussion to first clinical assessment were significant predictors of clinical outcomes. Statistically significant variables were included as covariates in a series of 1-way analyses of covariance to identify differences in balance, symptom severity, total symptom presence, and neurocognitive domain performance between students and athletes. Fisher exact tests were used to compare health history information between groups (α0.05).Among students, 24% reported sustaining a concussion while participating in recreational sports, and 27% of impacts occurred to the back of the head. Students had higher proportions of headache, migraine, anxiety, and depression (P.05). Students reported greater total symptom presence (P=.006) and performed worse on the computerized neurocognitive test domain score for complex attention (P=.015) relative to athletes.These findings highlight the need for better access to medical care for non- National Collegiate Athletic Association sanctioned athletes because of a large proportion of concussions in the student sample being sustained during sports participation. Identifying common injury mechanisms can provide clinicians with powerful information to improve evaluation and treatment models.

Context: Reaction time is commonly assessed postconcussion through a computerized neurocognitive battery. Although this measure is sensitive to postconcussion deficits, it is not clear if computerized reaction time reflects the dynamic reaction time necessary to compete effectively and safely during sporting activities. Functional reaction time assessments may be useful postconcussion, but reliability must be determined before clinical implementation. Objective: To determine the test–retest reliability of a functional reaction time assessment battery and to determine if reaction time improved between sessions. Design: Cohort. Setting: Laboratory. Participants: Forty-one participants (21 men and 20 women) completed 2 time points. Participants, on average, were 22.5 (2.1) years old, 72.5 (11.9) cm tall, had a mass of 71.0 (13.7) kg, and were mostly right leg and hand dominant (92.7%). Interventions: Participants completed 2 clinical reaction time tests (computerized Stroop and drop stick) and 5 functional reaction time tests (gait, jump landing, single-leg hop, anticipated cut, and unanticipated cut) across 2 sessions. Drop stick and functional reaction time assessments were performed in single (motor task only) and dual task (motor task with cognitive task). Main Outcome Measures: Reaction time (in seconds) was calculated during all assessments. Test–retest reliability was determined using 2-way mixed-effects intraclass correlation coefficients (3, k). Paired samples t tests compared mean reaction time between sessions. Results: Test–retest reliability was moderate to excellent for all reaction time outcomes (intraclass correlation coefficients [3, k] range = .766–.925). Several statistically significant between-session mean differences were observed, but effect sizes were negligible to small (d range = 0.05–0.44). Conclusions: The functional reaction time assessment battery displayed similar reliability to the standard computerized reaction time assessment battery and may provide important postinjury information, but more research is needed to determine clinical utility.

Background This study determined the effect of video-verified collision characteristics on head impact magnitudes in male youth tackle football. Methods Participants (n = 23, age = 10.9 ± 0.3 years, height = 150.0 ± 8.3 cm, mass = 41.6 ± 8.4 kg) wore Triax Sim-G sensors throughout the fall 2019 season. Ten filmed games were used to identify nine different collision characteristics: mechanism, preparedness, head direction, struck versus striking activity, stance, play type, closing distance, penalty, and quarter. Random-effects general linear models and Cohen d effect sizes were used to examine differences in log-transformed peak linear (PLA; g) and rotational (PRA; rad/s2) accelerations across characteristics. The 10 games produced 533 total video-verified impacts and 23.2 ± 7.2 impacts per athlete. Results PLA (P range: 0.107 to 0.923) and PRA (P range: 0.057 to 0.768) did not differ across characteristics. Struck players (3370 rads/s2, 95% confidence interval [CI] = 2986 to 3808) had a small effect for higher PRA compared with striking players (3037 rads/s2, 95% CI = 2713 to 3404, d = 0.251), but negligible effect for simultaneous struck-striking players (3340 rad/s2, 95% CI = 2945 to 3792, d = 0.018). Fourth quarter impacts (3490 rads/s2, 95% CI = 3083 to 3951) had a small effect for higher PRA compared with first (2945 rads/s2, 95% CI = 2596 to 3337, d = 0.404), second (3196 rads/s2, 95% CI = 2832 to 3604, d = 0.219), and third quarters (3241 rads/s2, 95% CI = 2841 to 3699, d = 0.144). Conclusion Youth tackle football characteristics did not significantly affect head impact magnitudes during games. More research is needed to explore additional factors that could be modified for sport safety rather than mitigating impact mechanism.

Shumski, EJ, Lempke, LB, Johnson, RS, Oh, J, Schmidt, JD, and Lynall, RC. Jump height and hip power decrease during cognitive loading regardless of sex: implications for sport performance metrics. J Strength Cond Res XX(X): 000-000, 2022-Sex and cognitive loading separately influence jumping performance. However, it is unknown how cognitive loading influences jump performance and how sex and cognitive loading interact. The purpose of our study was to determine if an interaction existed between sex and cognitive loading for the dependent variables jump height, ground contact time, reactive strength index, vertical stiffness, impulse, and lower extremity joint power during a double limb drop vertical jump. Twenty-one male (23.2 ± 2.5 years, 180.8 ± 8.4 cm, 80.4 ± 10.2 kg) and 20 female (21.7 ± 1.0 years, 163.7 ± 8.2 cm, 61.2 ± 9.4 kg) physically active individuals participated. Subjects jumped from a 30 cm box placed 50% of their height away from 2 force plates under single-task and dual-task (serial 6s or 7s) conditions. Separate 2 × 2 analyses of variance were used for all dependent variables (α = 0.05) with Bonferroni post hoc mean differences and 95% confidence intervals (CIs). There were no significant interactions for any outcomes (p ≥ 0.190). Condition main effects demonstrated subjects jumped significantly higher (1.84 cm, 95% CI = 0.68-3.01, d = 0.26, p = 0.003) and with greater hip power (0.29 Watts·BW-1·HT-1, 95% CI = 0.04-0.54, d = 0.21, p = 0.025) during single task compared with dual task. Sex main effects revealed males jumped higher (9.88 cm, 95% CI = 7.00-12.77, d = 2.17, p0.001), with greater reactive strength index (0.29, 95% CI = 0.17-0.41, d = 1.52, p0.001), greater ankle power (3.70 Watts·BW-1·HT-1, 95% CI = 2.26-5.13, d = 1.64, p0.001), and greater knee power (5.00 Watts·BW-1·HT-1, 95% CI = 3.25-6.75, d = 1.82, p0.001) compared with females. Jump performance is influenced by sex and dual-task conditions but not their interaction. To optimize jumping performance, testing should be completed without distractions (single task) to decrease cognitive loading.

Background: Youth flag football participation has rapidly grown and is a potentially safer alternative to tackle football. However, limited research has quantitatively assessed youth flag football head impact biomechanics. Purpose: To describe head impact biomechanics outcomes in youth flag football and explore factors associated with head impact magnitudes. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We monitored 52 player-seasons among 48 male flag football players (mean ± SD; age, 9.4 ± 1.1 years; height, 138.6 ± 9.5 cm; mass, 34.7 ± 9.2 kg) across 3 seasons using head impact sensors during practices and games. Sensors recorded head impact frequencies, peak linear ( g) and rotational (rad/s2) acceleration, and estimated impact location. Impact rates (IRs) were calculated as 1 impact per 10 player-exposures; IR ratios (IRRs) were used to compare season, event type, and age group IRs; and 95% CIs were calculated for IRs and IRRs. Weekly and seasonal cumulative head impact frequencies and magnitudes were calculated. Mixed-model regression models examined the association between player characteristics, event type, and seasons and peak linear and rotational accelerations. Results: A total of 429 head impacts from 604 exposures occurred across the study period (IR, 7.10; 95% CI, 4.81-10.50). Weekly and seasonal cumulative median head impact frequencies were 1.00 (range, 0-2.63) and 7.50 (range, 0-21.00), respectively. The most frequent estimated head impact locations were the skull base (n = 96; 22.4%), top of the head (n = 74; 17.2%), and back of the head (n = 66; 15.4%). The combined event type IRs differed among the 3 seasons (IRR range, 1.45-2.68). Games produced greater IRs (IRR, 1.24; 95% CI, 1.01-1.53) and peak linear acceleration (mean difference, 5.69 g; P = .008) than did practices. Older players demonstrated greater combined event–type IRs (IRR, 1.46; 95% CI, 1.12-1.90) and increased head impact magnitudes than did younger players, with every 1-year age increase associated with a 3.78 g and 602.81-rad/s2 increase in peak linear and rotational acceleration magnitude, respectively ( P≤ .005). Conclusion: Head IRs and magnitudes varied across seasons, thus highlighting multiple season and cohort data are valuable when providing estimates. Head IRs were relatively low across seasons, while linear and rotational acceleration magnitudes were relatively high.

Context: Concussions are shown to hinder multiple health dimensions, including health-related quality of life (HRQOL), suggesting a need for a whole-person approach to assessment and treatment. Patient-reported outcome measures are one method to gather the patient’s perspective regarding their HRQOL. Objective: To evaluate perceived HRQOL using the Patient-Reported Outcomes Measurement Information System Pediatric-25 subscale in patients throughout concussion recovery. Design: Prospective cohort, descriptive survey. Setting: There were 9 high school athletic training facilities. Participants: A total of 70 patients with diagnosed concussions (51 males, 7 females, 12 unreported; age = 15.7 [0.9] y, height = 174.6 [8.4] cm, mass = 72.8 [14.8] kg, grade = 10.0 [0.9] level). Interventions: Patient-Reported Outcomes Measurement Information System Pediatric-25 was administered at 3 days, 10 days postconcussion, and return to play (RTP). Main Outcome Measures: Patient-Reported Outcomes Measurement Information System Pediatric-25 subscale T scores and self-reported concussion history (yes/no). Results: A total of 70 patients completed the study. For the Pediatric-25 subscales, the severity of problems associated with Physical Function Mobility, Anxiety, Depression, Fatigue, and Pain Interference were highest 3 days postconcussion, decreasing at 10 days and RTP (all p p p > .05). Ceiling and floor effects were present in all subscales throughout each timepoint, except for Physical Function Mobility (14.7%), and pain interference (11.8%) at day 3 postinjury. Conclusions: Patients who had suffered a concussion improved from day 3 through RTP on multiple health domains as demonstrated through the Pediatric-25 subscales. These findings highlight the need for health care professionals to serially monitor HRQOL and social factors that may affect the patient postconcussion as part of a multifactorial assessment. Ceiling effects in high functioning adolescent athletes were present; thus, efforts should be made to identify appropriate scales for use in managing recovery in athletic populations.

PURPOSE This study aimed to examine the association between clinical and functional reaction time (RT) assessments with and without simultaneous cognitive tasks among healthy individuals. METHODS Participants (n = 41, 49% female; 22.5 ± 2.1 yr; 172.5 ± 11.9 cm; 71.0 ± 13.7 kg) completed clinical (drop stick, Stroop) and functional (gait, jump landing, single-leg hop, anticipated cut, unanticipated cut) RT assessments in random order. All RT assessments, except Stroop and unanticipated cut, were completed under single- (movement only) and dual-task conditions (movement and subtracting by 6s or 7s). Drop stick involved catching a randomly dropped rod embedded in a weighted disk. Stroop assessed RT via computerized neurocognitive testing. An instrumented walkway measured gait RT when center-of-pressure moved after random stimulus. All other functional RT assessments involved participants jumping forward and performing a vertical jump (jump landing), balancing on one leg (single-leg hop), or a 45° cut in a known (anticipated cut) or unknown (unanticipated cut) direction. RT was determined when the sacrum moved following random visual stimulus. Pearson correlation coefficients and a 5 × 2 repeated-measures ANOVA compared RT assessments and cognitive conditions. RESULTS Stroop RT outcomes did not significantly correlate with functional RT assessments (r range = -0.10 to 0.24). A significant assessment by cognitive task interaction (F4,160 = 14.01; P < 0.001) revealed faster single-task RT among all assessments compared with dual-task (mean differences, -0.11 to -0.09 s; P < 0.001), except drop stick (P = 0.195). Single-leg hop (0.58 ± 0.11 s) was significantly slower compared with jump landing (0.53 ± 0.10 s), anticipated cut (0.49 ± 0.09 s), gait (0.29 ± 0.07 s), and drop stick (0.21 ± 0.03 s; P values ≤ 0.001). Dual-task assessments were significantly slower than single-task assessments (mean difference, 0.08 s; P < 0.001). CONCLUSIONS Clinical and functional RT assessments were not correlated with each other, suggesting that sport-like RT is not being assessed after concussion. Functional and dual-task RT assessments may add clinical value and warrant further exploration after concussion.

Context: With growing concerns surrounding exposure to head impacts in youth tackle football, it is essential that parents and players understand the exposure level when consenting/assenting to participate. Objective: We aimed to determine whether youth football parents and players could estimate on-field head impact frequency, severity, and location. Design: Prospective Cohort Study Setting: On-field Patients or Other Participants: We administered a 10-question head impact estimation tool to parents (N=23; 36.5, 95% CI: 31.7, 37.3) and players (N=16; Age: 11.1, 95%CI: 10.3,11.8). Main Outcome Measures: Player on-field head impact exposure was captured using the Triax SIM-G system. We determined the accuracy between parent and players estimates relative to on-field head impact exposures using kappa and weighted kappa values. Results: Youth tackle football parents and players do not accurately estimate on-field head impact frequency (kappa range:−0.09–0.40), severity (kappa range: −0.05–0.34), or location (kappa range: −0.30–0.09). Parents and players overestimated head impact frequency in practices, but underestimated the frequency in games. Parents and players overestimated head impact severity, particularly in games. Most parents and players underestimated the number of head impacts to the top of the head, particularly during practices. Conclusions: Underestimations in head impact frequency in games and to the top of the head suggest that informed consent processes aimed at educating parents and players should be improved. Overestimations in head impact frequency in practices and severity may explain declining rates of youth tackle football participation.

Our purpose was to describe the youth flag football head impact burden and make comparisons with youth tackle football. Head impact frequency and magnitude (linear acceleration [g], rotational acceleration [rad/s

Context: Laboratory-based movement assessments are commonly performed without cognitive stimuli (ie, single-task) despite the simultaneous cognitive processing and movement (ie, dual task) demands required during sport. Cognitive loading may critically alter human movement and be an important consideration for truly assessing functional movement and understanding injury risk in the laboratory, but limited investigations exist. Objective: To comprehensively examine and compare kinematics and kinetics between single- and dual-task functional movement among healthy participants while controlling for sex. Design: Cross-sectional study. Setting: Laboratory. Patients (or Other Participants): Forty-one healthy, physically active participants (49% female; 22.5 ± 2.1 y; 172.5 ± 11.9 cm; 71.0 ± 13.7 kg) enrolled in and completed the study. Intervention(s): All participants completed the functional movement protocol under single- and dual-task (subtracting by 6s or 7s) conditions in a randomized order. Participants jumped forward from a 30-cm tall box and performed (1) maximum vertical jump landings and (2) dominant and (3) nondominant leg, single-leg 45° cuts after landing. Main Outcome Measures: The authors used mixed-model analysis of variances (α = .05) to compare peak hip, knee, and ankle joint angles (degrees) and moments (N·m/BW) in the sagittal and frontal planes, and peak vertical ground reaction force (N/BW) and vertical impulse (Ns/BW) between cognitive conditions and sex. Results: Dual-task resulted in greater peak vertical ground reaction force compared with single-task during jump landing (mean difference = 0.06 N/BW; 95% confidence interval [CI], 0.01 to 0.12; P = .025) but less force during dominant leg cutting (mean difference = −0.08 N/BW; 95% CI, −0.14 to −0.02; P = .015). Less hip-flexion torque occurred during dual task than single task (mean difference = −0.09 N/BW; 95% CI, −0.17 to −0.02). No other outcomes were different between single and dual task (P ≥ .053). Conclusions: Slight, but potentially important, kinematic and kinetic differences were observed between single- and dual-task that may have implications for functional movement assessments and injury risk research. More research examining how various cognitive and movement tasks interact to alter functional movement among pathological populations is warranted before clinical implementation.

Context: Gait termination time (GTT) has been used to predict falls in older adults but has not been explored in the sport rehabilitation setting. The incorporation of a concurrent cognitive task as a complex measure of gait in this clinical population could lead to better health-related outcomes. Objective: To compare the effect of planned and unplanned gait termination with and without a concurrent cognitive task on reaction time (RT), gait velocity, and GTT. Design: Cross-sectional. Setting: Laboratory. Participants: Twenty young adults (females 60.0%, age 20.1 [0.9] y, height 169.5 [8.8] cm, mass 67.4 [10.8] kg). Intervention: Participants completed 6 planned and 6 unplanned gait termination trials on an instrumented gait mat with and without a cognitive task. Main Outcome Measures: The authors measured RT (s), gait velocity (m/s), GTT (s), and normalized GTT (s2/m). A 2 (motor) × 2 (cognitive) repeated-measures analysis of variance (α = .05) was used; significant interaction effects were explored using Bonferroni-corrected t tests (α Results: Participants walked more slowly during dual-task trials compared with single-task trials (F1,19 = 4.401, P = .050). Participants walked significantly more slowly with a cognitive task during planned (P P = .001, mean difference = −0.111 m/s, 95% CI, −0.173 to −0.050) gait termination. Participants walked significantly more slowly (P F1,19 = 16.375, P = .001, mean difference = −0.118 s, 95% CI, −0.178 to −0.057) and slowed normalized GTT (F1,19 = 5.655, P = .028, mean difference = −0.167 s2/m, 95% CI, −0.314 to −0.020). Conclusions: Overall, participants displayed more conservative gait strategies and slower RT, normalized GTT, and gait velocity as task difficulty increased. More investigation is needed to truly understand the clinical meaningfulness of these measures in athletic injuries.

This study aimed to examine the association between clinical and functional reaction time (RT) assessments with and without simultaneous cognitive tasks among healthy individuals.Participants (n = 41, 49% female; 22.5 ± 2.1 yr; 172.5 ± 11.9 cm; 71.0 ± 13.7 kg) completed clinical (drop stick, Stroop) and functional (gait, jump landing, single-leg hop, anticipated cut, unanticipated cut) RT assessments in random order. All RT assessments, except Stroop and unanticipated cut, were completed under single- (movement only) and dual-task conditions (movement and subtracting by 6s or 7s). Drop stick involved catching a randomly dropped rod embedded in a weighted disk. Stroop assessed RT via computerized neurocognitive testing. An instrumented walkway measured gait RT when center-of-pressure moved after random stimulus. All other functional RT assessments involved participants jumping forward and performing a vertical jump (jump landing), balancing on one leg (single-leg hop), or a 45° cut in a known (anticipated cut) or unknown (unanticipated cut) direction. RT was determined when the sacrum moved following random visual stimulus. Pearson correlation coefficients and a 5 × 2 repeated-measures ANOVA compared RT assessments and cognitive conditions.Stroop RT outcomes did not significantly correlate with functional RT assessments (r range = -0.10 to 0.24). A significant assessment by cognitive task interaction (F4,160 = 14.01; P0.001) revealed faster single-task RT among all assessments compared with dual-task (mean differences, -0.11 to -0.09 s; P0.001), except drop stick (P = 0.195). Single-leg hop (0.58 ± 0.11 s) was significantly slower compared with jump landing (0.53 ± 0.10 s), anticipated cut (0.49 ± 0.09 s), gait (0.29 ± 0.07 s), and drop stick (0.21 ± 0.03 s; P values ≤ 0.001). Dual-task assessments were significantly slower than single-task assessments (mean difference, 0.08 s; P0.001).Clinical and functional RT assessments were not correlated with each other, suggesting that sport-like RT is not being assessed after concussion. Functional and dual-task RT assessments may add clinical value and warrant further exploration after concussion.

Background: There is growing fear among healthcare professionals and parents regarding youth tackle football, likely due to highly publicized concerns about potential long-term physical and cognitive health of professional football players. Parents and advocacy groups are pushing for state legislation to ban youth tackle football in favor of flag football to avoid repetitive head impacts that are potentially associated with late-life cognitive deficits. Although the head impact burden experienced during flag football is likely lower than tackle, no research has compared head impact exposure between youth tackle and flag football. Therefore, our purpose was to examine head impact exposure and magnitudes between youth tackle and flag football players. Methods: Twenty-seven tackle (age=11.0±1.5y, height=145.8±11.9 cm, mass=45.0±14.9 kg) and 29 flag football players (age=8.6±1.1y, height=133.9±8.4 cm, mass=33.9±9.5 kg) were enrolled in this prospective cohort study. Participants were fitted with head impact sensors (Triax Sim-G) worn throughout the entire 2017 season that recorded impact frequency and magnitude (linear [g] and rotational acceleration [rad/s2]). Athlete exposure was defined as one player participating in one session. Impact rates (IR) were calculated as impacts per one athlete exposure. Game, practice, and combined IR were compared between groups using impact rate ratios (IRR). IRR with 95% confidence intervals (CI) not containing 1.0 were considered statistically significant. Acceleration values were binned into low- and high-magnitude categories (linear split at 40 g, rotational split at 4,600rad/s2). Magnitude category frequencies were compared between groups using Chi-square test of association (pResults: One-thousand nine-hundred and eight tackle (735 game, 1173 practice; 70.66 impacts/player) and 169 flag (101 game, 68 practice; 5.83 impacts/player) football head impacts were recorded. Tackle players experienced a higher impact rate during games versus practices (IRR=1.41; 95%CI:1.29 -1.55) while flag players experienced a lower impact rate (IRR=0.60; 95%CI:0.44-0.81). Practice and game head impacts combined resulted in tackle players (IR=3.06) accruing 4.61 times the impact rate (95%CI:3.94-5.40) of flag players (IR=0.66). Tackle players sustained a significantly greater head impact rate than flag players during games (tackle IR=3.83, flag IR=0.55; IRR=6.90; 95%CI:5.60-8.49) and practices (tackle IR=2.72, flag IR=0.93; IRR=2.91; 95%CI:2.28-3.72). Tackle 90th percentile linear acceleration was 53.32 g (median=32.50 g) and flag was 53.32 g (median=32.65 g). Tackle 90th percentile rotational acceleration was 7,000 rad/s2 (median=3,200rad/s2) while flag was 8,300 rad/s2 (median=4,100rad/s2). Tackle experienced a significantly higher frequency of low-magnitude rotational acceleration impacts (71.6% vs. 57.4%) and lower frequency of high-magnitude impacts than flag (28.4% vs 42.6%;?2=15.15, pConclusions/Significance: Our results indicate youth flag football head impact rates are 82%-88% lower compared to tackle. Contrary to general belief, youth flag football players experienced numerous head impacts with a greater tendency for high-magnitude rotational acceleration head impacts. Although fewer head impacts occur during youth flag football, parents and coaches should be aware that head impacts do occur during practices and games. Whether high-magnitude or high-frequency head impacts influence long-term health remains unknown. Our findings provide novel evidence into the head impact exposure occurring during youth tackle and flag football. Longitudinal studies examining head impact biomechanics and advanced neuroimaging in youth tackle and flag football players nationwide is warranted to ensure long term cognitive health.

Clinical Scenario:It is hypothesized that cognitive activity following a concussion may potentially hinder patient recovery. While the recommendation of cognitive rest is often maintained and rationalized, a causal relationship between cognitive activity and symptom duration has yet to be established.Clinical Question:Does the implementation of cognitive rest as part of the postconcussion management plan reduce the number of days until the concussed adolescent patient is symptom free compared to a postconcussion management plan that does not incorporate cognitive rest?Summary of Key Findings:A thorough literature search returned 7 possible studies; 5 studies met the inclusion criteria and were included. Three studies indicated that increased cognitive activity is associated with longer recovery from a concussion, and, therefore, supported the use of cognitive rest. One study indicated that the recommendation for cognitive rest was not significantly associated with time to concussion symptom resolution. One study indicated that strict rest, defined as 5 days of no school, work, or physical activity; might prolong symptom duration.Clinical Bottom Line:There is moderate evidence to support the prescription of moderate cognitive rest for concussed patients. Clinicians who intend on implementing cognitive rest in their concussion protocols should be aware of inconsistencies and be open-minded to alternative treatment progressions while taking into consideration each individual patient and maintaining adequate patient-centered care principles.Strength of Recommendation:Grade B evidence exists that prescription of moderate cognitive rest for concussed patients may be beneficial as a supplement to physical rest as treatment for symptom reduction in adolescents.

We explored 2-year-olds’ developing self-conceptions by examining uses of terms for the self ( I , me , own name) to mark contexts of self-action that varied in transitivity. Children differed in their preferred terms for self-reference ( I versus proper name/ me ). “I-users” produced relatively more verbs for highly transitive events that encode subjective experiences of intention and agency and “Name-users” produced relatively more verbs for intransitive events that encode objective experiences of self in motion, even though verb and self-reference vocabularies were similar for the two groups. Results are discussed in terms of children's creative use of language to construct different developmental paths toward self-conceptions and acquisition of the personal pronoun system.