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The effect of time-of-day on static and dynamic balance in recreational athletes
Abstract
The purpose of this study was to investigate the effect of time-of-day (morning vs. afternoon) on static and dynamic balance in recreational athletes. A total of 34 recreational athletes completed the single-leg stance test with or without eyes open, lower quarter Y-balance test, upper quarter Y-balance test, and single-leg landing balance test in a random order in the morning (7:00–10:00 am) and afternoon (3:00–6:00 pm) for two consecutive days. Compared with the morning, participants demonstrated decreased centre of pressure (COP) sway areas (p = 0.002; Cohen’s d (d) = 0.28) and sway speeds (p = 0.002; d = 0.17) during the eyes-open single-leg stance test, increased stance time (p = 0.031; d = 0.16) and decreased COP sway areas (p = 0.029; d = 0.22) during the eyes-closed single-leg stance test, and increased reaching distances (p = 0.024; d = 0.10) during the upper quarter Y-balance test in the afternoon. The between-day effect (day 1 vs. day 2) was observed for several parameters. Time-of-day had a minimal effect on dynamic balance and a noticeable effect on static balance. Time-of-day may be considered as a factor in designing balance training programmes and intervention studies for recreational athletes.
... That is, cognitive performance and metabolic function, which can influence mental and physical performance, including strength and flexibility [4], fluctuate during a 24-hour period, whereby several human functions can be expected to act optimally when the aforementioned variables are at a high value [2,5]. In this context, it has been suggested that PC can be varied at different times of the day [6,7]. However, several studies have not demonstrated any significant differences between PC and time of day [8][9][10]. ...
... After removing 2958 duplicates, the titles and abstracts of the remaining 6549 studies were screened for qualification. The full text of 88 studies were evaluated in accordance with the inclusion and exclusion criteria wherein 46 articles [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] were eligible for this systematic review. Finally, 3 studies [55][56][57] were added via hand-searching of the included studies' references for a total of 49 studies. ...
... A total of 1296 healthy subjects participated in all studies in which their age range was between 5.6 and 85.2 years. In twenty-five studies [6,7,10,11,[16][17][18][19]23,24,29,30,34,40,[43][44][45][48][49][50][51][52][53]56,57], both males and females were included, while 7 studies did not report the sex of subjects [13,14,[35][36][37]54,55]. Sixteen studies [8,9,12,15,[20][21][22]28,[31][32][33]38,41,42,46,47] included only male participants and one study included only females [39]. ...
Background
Postural control (PC) can be affected by circadian rhythm and sleep deprivation, whereby it has been reported the result of PC measurement in clinical and experimental situations can be influenced by both factors. It has been suggested sleepiness can result in deficiency in PC, which in turn can lead to occupational accidents and subsequent injuries. This is while no study critically reviews or summarizes findings surrounding this topic in the literature.
Research question
Is there any significant effect of sleep deprivation and circadian rhythm on PC variables among healthy individuals?
Methods
PubMed, Web of Science, Scopus, and Embase were used to detect relevant studies. Only studies that examined the effect of time of day and/or sleep loss on PC among healthy individuals were included in this systematic review.
Results
Forty-nine studies were included based on the inclusion criteria. Both circadian rhythm and sleep loss had a significant effect on PC, whereas there are inconsistent findings for optimal postural control regarding time of day. In terms of sleep deprivation, all investigations indicated that sleep loss deteriorates PC.
Significance
The current systematic review represents a significant effect of circadian rhythm and sleep deprivation on PC, whereby it is suggested that clinicians and researchers consider these factors when measuring PC since it may affect the result of research and clinical test. Moreover, PC may be worsened through sleeplessness; however, some studies revealed there is no linear relationship between time of wakefulness and deteriorating PC due to the influence of circadian rhythm. Hence, while PC, as an objective tool, can help to detect those who are sleep deprived, which in turn can lead to prevent possible musculoskeletal injuries, further studies are needed to reveal more understanding about the effect of sleep loss and circadian rhythm on PC.
... Furthermore, athletes may (i) have better postural performance compared with non-athletes and (ii) may develop specific postural abilities according to the specificity of the sport practiced (Hrysomallis 2011). In this context, some authors have examined the diurnal rhythm of postural stability in trained young adults (Heinbaugh et al. 2015;Russo et al. 2015). In fact, Heinbaugh et al. (2015) found out an increased static postural performance in the afternoon (habitual hour of training) compared to the morning, and a minimal effect of time-of-day when performing dynamic postural tasks. ...
... In this context, some authors have examined the diurnal rhythm of postural stability in trained young adults (Heinbaugh et al. 2015;Russo et al. 2015). In fact, Heinbaugh et al. (2015) found out an increased static postural performance in the afternoon (habitual hour of training) compared to the morning, and a minimal effect of time-of-day when performing dynamic postural tasks. However, Russo et al. (2015) revealed the absence of significant timeof-day effect on postural stability in young sportsmen aged between 18 and 30 years. ...
... Similar findings were found in sedentary age matched children (Baccouch et al. 2015). Similarly, in recreational athletes (23 years old), the static balance performance was low in the morning session that was set between 07:00 and 10:00 h (Heinbaugh et al. 2015). By way of contrast, Russo et al. (2015) have revealed the absence of significant time-of-day effects on postural stability in young sportsmen aged between 18 and 30 years. ...
The present study aimed to investigate the diurnal variation of postural stability, attentional capacities, and oral temperature in 5–6-year-old tennis players. A total of 24 young children were divided into two groups: Twelve tennis players with 2 years of training experience and twelve sedentary children without previous experience in any type of sport. They were asked to maintain an upright bipedal stance on a static force platform with eyes open (EO) and eyes closed (EC) at 07:00, 10:00, 14:00, and 18:00 h. Postural stability was evaluated by the center of pressure (CoP), surface area (CoPArea), CoP mean velocity (CoPVm), and Romberg’s index (RI). Oral temperature and simple reaction time (SRT) were also recorded at the beginning of each test session. Postural stability in 5–6-year-old tennis players was low at 07:00 h and improved at 10:00 h (p < 0.001); then, it worsened at 14:00 h (p < 0.001) and improved again at 18:00 h (p < 0.001) as found in sedentary children. This rhythm was also close to that of SRT in both groups. Body temperature increased significantly (p < 0.001) from the morning to the afternoon in both groups. However, the peak of postural performance, the peak of attentional capacities, and the greatest vision contribution to maintain balance observed at 18:00 h were only found in the trained group. Moreover, young tennis players were more stable (p < 0.001) and more attentive (p < 0.01) than sedentary ones at 18:00 h. The amplitude of the diurnal rhythm of CoP parameters was significantly larger (p < 0.01) in trained children compared to sedentary ones (43.1 ± 8.5 vs 31.7 ± 8.3 for the CoPArea; 27.5 ± 7.4 vs 17.7 ± 8.2 for the CoPVm). Therefore, time-of-day has a significant effect on static postural stability and attentional capacities in young tennis players with better performances in the late afternoon (habitual hour of training). Thus, we recommend planning some training sessions at 07:00 and/or 14:00 h to optimize postural stability at the time of its batyphase and to reduce the incidence of fall-related injury risks during this critical age in athletic environments.
... 14 These theories are further supported by an increase in match play American Football (NFL) injuries that have been shown to correspond with match start times, which are nearer to endogenous biological troughs in alertness, thus accentuating fatigue and injury risk. 14 Physical performance variations with time of day have been observed in measures of dynamic and static postural control [15][16][17] and measures of isokinetic knee strength, 18 tasks that are commonly used during screening of athletes. However, most studies [15][16][17][18] investigating circadian variation and etiological risk factors have involved nonsporting populations, while often only including a single outcome measure. ...
... 14 Physical performance variations with time of day have been observed in measures of dynamic and static postural control [15][16][17] and measures of isokinetic knee strength, 18 tasks that are commonly used during screening of athletes. However, most studies [15][16][17][18] investigating circadian variation and etiological risk factors have involved nonsporting populations, while often only including a single outcome measure. Given the multifactorial nature of sports injury etiology, 7 the influence of circadian variation should be applied to a battery of etiological tests that better represent the epidemiology and etiology of particular sports. ...
... Previous research [15][16][17][18] appears to be influenced by reduced participant ability and training status. It has been suggested that athletes display improved levels of postural stability when compared with the general population, 19 while also possessing enhanced athletic abilities at times of the day where they regularly train or perform. ...
Context:
Clinical and functional assessments are performed regularly in sporting environments to screen for performance deficits and injury risk. Circadian rhythms have been demonstrated to affect human performance, however the influence of time of day on a battery of multiple ankle injury risk factors has yet to be established within athletic populations.
Objectives:
To investigate the influence of circadian variation on a battery of tests, used to screen for ankle aetiological risk factors.
Design:
Randomised crossover design.
Setting:
University laboratory.
Participants:
Thirty-three semi-professional soccer players (age 24.9 ± 4.4 years; height 1.77 ± 0.17 m; body mass 75.47 ± 7.98 kg) completed three randomized experimental trials (07:00 h, 12:00 h, 19:00 h) Main Outcome Measures: Trials involved the completion of a standardized test battery comprising Biodex Stability System (BSS), Star Excursion Balance Test (SEBT), isokinetic inversion: eversion ratio, joint position sense, and a drop landing inversion cutting manoeuvre.
Results:
Repeated measures analysis of variance revealed significantly (P < 0.05) lower values for all BSS indicia; Overall Stability Index (1.10 ± 0.31 a.u), Anterior-Posterior (0.76 ± 0.21 a.u) and Medio-Lateral (0.68 ± 0.23) at 12:00 h when compared to 07:00 h. (1.30 ± 0.45 a.u; 0.96 ± 0.26 a.u; 0.82 ± 0.40 a.u) respectively. However, no significant (P ≥ 0.05) main effects for time of day were reported for any other test.
Conclusions:
Circadian influence on ankle aetiological risk factors was task dependent, with measures of proprioception, strength and SEBT displaying no circadian variation, indicating no association between time of day and markers of injury risk. However, the BSS displayed improved performance at midday, indicating postural stability tasks requiring unanticipated movements to display a time of day effect and potential increased injury risk. Consequently, time of testing for this task should be standardized to ensure correct interpretations of assessments and/or interventions.
... One study did not specify the type of reliability reported as a secondary outcome (Gottlieb et al., 2018), with ICC ranging from 0.80 to 0.89. In addition, it has been confirmed that there is a negligible effect of time of day on UQYBT scores (Heinbaugh et al., 2015). ...
The aim of this scoping review was to comprehensively examine the Upper Quarter Y-Balance Test (UQYBT), including reference values, reliability, determinants, and its practical application. By including studies irrespective of publication date, participant demographics, or research purpose, provided they were in English and incorporated UQYBT as a primary or secondary variable, an extensive dataset was collected. The focus was on limb-length-normalized results to establish standardized reference metrics. Reliability studies highlighted the UQYBT’s consistency across sessions and raters. The application of UQYBT to assess injury risk is questionable. Studies assessing its relationship with sports performance have also yielded varying results. UQYBT seems to be sensitive to various exercise based-interventions, as shown by several clinical trials. This review furnishes practitioners and clinicians with valuable insights for the application of UQYBT in sports and healthcare settings.
... It is known that the time effect is minimal on balance performance. 22 Thus, further study will be required to examine the effect of the onset of thirst on balance performance. Unlike the result of the current study, the previous study shows 2.6% dehydration, induced by exercise heat exposure, and decreased BESS performance. ...
Objective
To examine the effects of euhydration, mild-dehydration, rehydration, and ad libitum drinking on countermovement jump (CMJ), handgrip strength, and performance of balance error scoring system test (BESS).
Methods
Eighteen healthy male subjects (mean[M]±standard deviation[SD]; age, 23±3y; body mass, 80.1 ± 9.7 kg; height, 175.8 ± 5.7 cm) participated in this study. Participants reported to the laboratory to perform CMJ, handgrip strength, and BESS with different hydration statuses (euhydrated, EUH; when they initially sensed thirst, THIRST; dehydrated, DEH; following 30 minutes of rehydration, REH; and following 24-h ad libitum drinking, AD).
Results
CMJ at EUH (M±SD; 54.6 ± 3.0 cm) was significantly higher than DEH (52.8 ± 3.0 cm, p = 0.027) and REH (52.6 ± 2.8 cm, p < 0.001). However, there was no difference between DEH and REH (p = 0.643). CMJ at THIRST (54.9 ± 3.0 cm, p = 0.004) was higher than REH. Also, AD (53.8 ± 2.8 cm, p = 0.027) was higher than REH. In left handgrip strength, THIRST (48.6 ± 9.5 kg) was higher than EUH (46.7 ± 10.1 kg, p = 0.018), DEH (45.8 ± 10.0 kg, p = 0.013), REH (46.1 ± 9.5 kg, p = 0.004), and AD (47.1 ± 9.7 kg, p = 0.05). Additionally, in the single-leg stance on a foam pad, more BESS errors were found at THIRST (6 ± 2) compared to EUH (5 ± 2, p = 0.007) and AD (5 ± 2, p = 0.002).
Conclusion
The findings of this study were: ∼2% of mild dehydration induced by 24-h fluid restriction decreased lower body power measured by CMJ, acute rehydration did not restore the loss of lower body power induced by dehydration, and ∼0.5–0.9% of dehydration did not decrease lower body power.
... In addition, no statistical differences in the dominant limb were reported (0.2-3.0%). Our results agree with previous studies in the literature that established that time-of-day had a minimal effect on dynamic balance in athletes (Heinbaugh et al. 2015). ...
This study aimed to determine if time-of-day could influence physical volleyball performance in females and to explore the relationship between chronotype and volleyball-specific performance. Fifteen young female athletes participated in a randomized counterbalanced trial, performing a neuromuscular test battery in the morning (9:00 h) and the evening (19:00 h) that consisted of volleyball standing spike, straight leg raise, dynamic balance, vertical jump, modified agility T-test and isometric handgrip tests. Chronotype was determined by the morningness-eveningness questionnaire. Compared to the morning, an increased performance was found in the standing spike (4.5%, p = .002, ES = 0.59), straight leg raise test (dominant-limb) (6.5%, p = .012, ES = 0.40), dynamic balance (non-dominant-limb) (5.0%, p = .010, ES = 0.57) and modified T-test (2.1%, p = .049, ES = 0.45) performance in the evening; while no statistical differences were reported in vertical jump tests or isometric handgrip strength. Moreover, no associations were found between chronotype and neuromuscular performance (r = −0.368–0.435, p = .052–0.439). Time-of-day affected spike ball velocity, flexibility in the dominant-limb, dynamic balance in the non-dominant-limb and agility tests. However, no association was reported among these improvements and the chronotype. Therefore, although the chronotype may not play critical role in volleyball-specific performance, evening training/matches schedules could benefit performance in semi-professional female volleyball players
... Enhanced postural control of the younger participants later in the day (Heinbaugh, Smith, Zhu, Wilson, & Dai, 2015) and reduced postural control of the older during the night (Duffy et al., 2002) have both been previously reported, although the second finding was not confirmed from the present study. Considering that the young group seems to be more affected by the time of day, the circadian circle may be a factor with greater impact on the younger, as far as balance is concerned, in whom age-related changes in the circadian rhythms has not yet taken place and transition toward morningness has not yet occurred (Van Someren, 2000). ...
Background:
Many physiologic parameters fluctuate on a diurnal basis following the circadian rhythm function. The purpose of the study was to investigate if postural performance is interdependent of time of day and age.
Methods:
19 young (22.63 ± 3.43 y.o.) and 19 older male adults (60.21 ± 3.67 y.o.) performed three balance tests (quiet stance with open and closed eyes and bipedal balance on a Togu ball) at 12:00 AM and at 12:00 PM. Time and frequency domain variables of the center of pressure were analyzed.
Results:
At eyes closed test, the younger had significant less distance traveled by the Center of Pressure (CoP) at night compared to day. At open eyes test, the younger had significant less CoP sway in the anterior-posterior (AP) axis at night compared to day. At Togu ball test the older showed increased peak-to-peak amplitude of CoP in both axes compared to younger. They also had lower frequency in the medial-lateral (ML) axis but higher in the AP axis compared to the younger.
Conclusion:
Younger seem to function better at night. There is also an indication that the older are better at day. The results on unstable surface indicate different control strategies between the two groups.
... In support of the current study, Gribble et al. (26) stated that the results obtained in the morning were better in terms of dynamic postural control than those obtained in the afternoon or evening. Heinbaugh et al. (27) showed similar results in terms of static balance. This may be due to better cognitive ability in the morning, which plays an important role in balance. ...
Purpose: Although there are many studies in the literature regarding the running of soccer players,
there is a need to examine the running asymmetry of the athletes' actual training, regardless of
a specific intervention protocol. The aim of this study was to compare the running asymmetry of
healthy elite soccer players in training sessions at different times of the day.
Methods: Sixteen healthy male elite soccer players were included in this study. Global Positioning
System units (GPSports, SPI Pro, 5 Hz, GPSport, Canberra, Australia) were used to define training
and running details. Fourteen (7 morning, 7 evening) training data were evaluated.
Results: There was no statistical difference between morning and evening trainings in terms
of training time, heart rate average and total running distance except for high speed running
distance. Running asymmetry was 66% greater in evening training sessions than in morning
training sessions (p=0.001; 4.13±1.92, 2.49±1.32 respectively). Running asymmetry did not show
any significant correlation with training time, heart rate average, running distance, and high speed
running distance (p>0.05).
Conclusion: Running asymmetry is higher in evening training sessions than in morning training
sessions. Therefore, for athletes who are particularly at high risk of injury or who are in the process
of a return to sports, and from whom high performance is not expected, morning trainings may be
preferred instead of evening trainings. If training can not be performed in the morning, clinicians
should follow the athletes instantly during evening training
... gravitation pull and moonlight) did not affect injuries incidence in soccer's professional's players. Since our finding demonstrated that the dynamic balance performance does not follow a circamonthly rhythm as circadian rhythm (Heinbaugh et al., 2015), other studies are needed to be demonstrated if the moon cycle affects balance performance in participants with other fitness levels and sporting specialties. Since Taekwondo athletes are characterized by good balance (Leong et al., 2011) and we speculate that other athletes with less well-developed balance qualities might eventually be impacted by the moon cycle. ...
Background:
Fascination with the moon has spanned millennia. It has recently been asserted that the moon cycle affects endurance performance in untrained individuals. The present study aimed at investigating the effects of the lunar cycle on intermittent endurance physical performance, balance and reaction-time capabilities, and selected physiological and psychological parameters in trained athletes.
Methods:
Twelve male Taekwondo athletes (age, 22.3 ± 0.8 years; height, 178.8 ± 6.5 cm; body mass, 72.75 ± 7.28 kg; %body fat, 13.9 ± 3.6%) performed the Yo-Yo intermittent recovery test level-1 (YYIRT), the Y-balance test (YBT), and a reaction-time test (RT) during different lunar cycle phases (new moon (NM), full moon (FM), and half-moon). Participants' psychological profiles and well-being indices (i.e. a profile of mood state (POMS) and Hooper index) were also taken during each moon phase. The testing sessions during the different moon phases were performed in a counterbalanced order. The tests order remained the same (POMS, then Hooper index, RT, YBT, YYIRT and rating of perceived exertion scale (RPE)), and all sessions were performed at noon (11:00 to 13:00 h) during the first day of each evaluated lunar phase.
Results:
Analysis of variance tests showed that no significant differences were found between the three moon phases in all analyzed variables.
Conclusions:
This study showed that the different lunar cycle phases did not have significant effects on the selected physical performances and psychological indices in trained athletes.
... In contrast to the results of these studies, Heinbaugh, Smith, Zhu, Wilson, and Dai [33] applied a dynamic balance test (Y Balance Test) to 34 physically active participants at 7:00-10:00 and 15:00-18:00. They reported that circadian rhythm had a minimal effect on dynamic balance. ...
Introduction. The aim of the study was to examine the effect of circadian rhythm on dynamic balance performance and to determine the role of physical activity level, body temperature, chronotype, and gender in this possible effect. Material and
methods. Forty-two young male and female subjects with different physical activity levels participated in the study. A dynamic equilibrium test, a Star Excursion Balance Test (SEBT), was conducted at 9:00, 13:00, and 17:00 on three different days with at least two days of interval between tests. The test scores were calculated by dividing the reaching distances by the leg length and multiplying the quotient by 100. The physical activity level and sleep state were evaluated using questionnaires. Before each test, body temperatures were measured orally. Results. The best SEBT scores were found at 13:00 and 17:00 in the male group and in the trained group. The body temperature changes increased parallel to SEBT scores. The scores for the non-dominant leg were found to be significantly different in posterior test directions, and those for the dominant leg were different in anterior directions. Chronotype did not affect the test results. Conclusions. Circadian rhythm was found to have an effect on dynamic balance performance. Body temperature, gender, and physical activity level were also found to play a role in this effect.
... Thus, upper extremity closed kinetic chain exercises should be added in shoulder rehabilitation programs". Heinbaugh et al. (2015) investigated the effect of time-of-day (morning vs. afternoon) on static and dynamic balance in recreational athletes. Time-of-day had a minimal effect on dynamic balance and a noticeable effect on static balance. ...
Circadian rhythms in the physiological and behavioral processes of humans play a crucial role in the quality of living and also in the magnitude of success and failure in various endeavors including competitive sports. The rhythmic activities of the body and performance in sportspersons do have a massive impact on their every cutthroat competition. It is essential to schedule sports activities and training of players according to their circadian typology and time of peak performance for improved performance and achievement. In this review, the focus is on circadian rhythms and diurnal variations in peak athletic performance in sportspersons. Accuracy and temporal variability in peak performance in an individual could be attributed to various factors, namely chronotype, time of the day, body temperature, jetlag, hormones, and prior light exposure. Circadian rhythm of mood, alertness, T-core, and ultimately athletic performance is not only affected by sleep but also by circadian variations in hormones, such as cortisol, testosterone, and melatonin. There are, however, a few reports that are not consistent with the conclusions drawn in this review. Nevertheless, circadian rhythm and performance among sportspersons and athletes are important areas of research. This review might be useful to the managers and policymakers associated with competitive sports and athletic events.
The study aimed to evaluate the effect of sleep deprivation on postural stability among physically active young adults. The study involved 22 physical education students. Average velocities and spatial distribution of the center of pressure displacements were taken as indicators of postural stability (double and one-leg standing). Two-way ANOVA with two factors of repeated measurements—“session” (control-experimental) and “daytime” (evening-morning)—was used. For indicators of the spatial distribution of the center of pressure in double stance with eyes open and eyes closed, and for average velocities for measurements with eyes closed, statistically significant interaction effects were found (at least p < 0.01, ƞ ² > 0.36, power statistics > 0.90) with the general tendency of higher results in the morning in the session with sleep deprivation than in the control session. In one-leg standing, an increase of average velocities was observed in the control session, and no differences in the session with sleep deprivation (interaction effect: at least p < 0.01, ƞ ² > 0.37, power statistics > 0.90). Besides spatial distribution indicators in double stance, there were no statistical differences between evening-morning tests in the session with sleep deprivation. Despite significant interaction effects, only the results of spatial distribution indicators in double stance were higher in the morning than in the evening in the session with sleep deprivation. So, no clear decline in postural stability after sleep deprivation was observed. This may suggest that sleep deprivation prevents natural regeneration rather than significantly worsening postural stability among physically active adults. It’s possible that systematic physical activity might be one of the factors decreasing the risk of accidents among people exposed to sleep deprivation.
Background:
Concussions or musculoskeletal injuries may impair postural control, which is one diagnostic to help determine return-to-activity decisions. Postural control may be affected by diurnal rhythm.
Research question:
Does time of day influence postural control as measured by two Neurocom Balance Master diagnostic protocols, the Modified Clinical Test of Sensory Interaction on Balance (mCTSIB) and the Stability Evaluation Test (SET)?
Methods:
Following Institutional Review Board (IRB) approval, consented participants completed the SET and mCTSIB twice: between 0700 and 1000; and between 1600 and 1900. We randomized and balanced testing order. Familiarization trials were completed for the mCTSIB and SET. Assessments were completed in a controlled laboratory environment. We instructed participants to get a normal night's sleep prior to testing and refrain from caffeine use and exhaustive exercise on the day of testing. Sixty-nine participants (48 female, 21 male: age = 21.42±2.56 years, height = 168.20±7.53 cm, mass = 72.05±16.60 kg) completed the study. Thirty-one of the participants were National Association of Intercollegiate Athletes (NAIA) student-athletes from the sports of baseball, soccer and softball. Average postural sway velocity was measured and compared by time of day for each of the balance conditions in the mCTSIB and SET protocols.
Results:
According to repeated measures ANOVA, there were no significant postural sway velocity main effects by time of day for any of the balance conditions. We found significant postural sway main effects by foam, stance and eyes. We also noted significant ANOVA between participants' differences for athlete status, but not for sex.
Significance:
These results inform practitioners about the importance of controlling time-of-day between baseline and post-injury testing, which may allow for more flexible, accurate and reliable diagnosis and return-to-activity decisions. Athletes displayed better static postural control, possibly warranting different normative values for diagnostic comparison.
Maintaining posture and movement stabilities, that is, balance, is particularly important for safety in daily life along with performing exercises. The purpose of this study was to clarify the changes in static and dynamic balance abilities from 8:00 to 18:00 and investigate the factors of change in balance ability among healthy young people. The subjects were nine relatively active healthy university students. The static and dynamic balance abilities were measured by a body sway test while static standing and the Cross Test, in which the center of gravity was voluntarily moved to the maximum in the front, back, left, and right directions, respectively. No change with time was observed in the static balance index. However, the maximum amplitude in the anteroposterior direction, an index of dynamic balance, significantly increased with time (8:00 vs 18:00, p<0.05). Sleepiness score significantly decreased with time (8:00 vs 18:00, p<0.05). As a result of simple correlation analysis, there were significant relationships between static balance indices (environmental area and rectangle area) and autonomic activity index (heart rate variability) at many times (p<0.05). Thus, it was concluded that the static balance ability was not affected by time. Furthermore, the ability to move the center of gravity in the anteroposterior direction of dynamic balance was low during morning and increased with time in relatively active healthy young people. Additionally, it was suggested that autonomic nervous activity was associated with static balance and the sleepiness was associated with dynamic balance.
Background and Aims Time-of-day is a factor that could affect balance performance. On the other hand, arousal fluctuates throughout the day. The aim of this study was to investigate the static balance performance prediction based on arousal and activation in circadian rhythm.
Methods In the current study, 30 healthy subjects (age= 21± 0.5 years) participated. Static balance performance was measured three times: 10:00 am, 15:00 pm, and 8:00 pm. Arousal was recorded continuously during the performance of the balance task. A balance scoring test (BESS) and a Bioderm device were used to measure static balance and arousal. Repeated measures ANOVA, Pearson correlation coefficient, and regression analysis were used to analyze the data.
Results Results indicated that balance performance was greater at 3:00 pm than at 8:00 pm and 10:00 am (P
Background:
Balance function is a key indicator in the identification of and recovery from concussion. The NeuroCom Sensory Organization Test (SOT) is used to objectively quantify balance using input from the visual, vestibular, and somatosensory systems. Baseline tests are necessary for comparison post-concussion.
Purpose:
The primary purpose of this study was to establish baseline SOT measures for the population that will be useful in the concussion assessment, diagnosis, and return to duty decisions following a concussion. Secondary aims were to compare females and males as well as concussed versus non-concussed. To the knowledge of the authors these are the only published normative data for a highly-active military population ages 17-23.
Study design:
Cross-sectional study.
Methods:
Two hundred fifty-three (70 female and 183 male) cadets in a boxing course at a service academy were enrolled. The participants were evaluated on the SOT using the NeuroCom Balance Manager (Natus Medical Inc., Seattle, WA) and each condition, composite (COMP) score, and ratio score were recorded.
Results:
No significant differences were observed in SOT COMP scores between females (COMP = 76.67 ± 7.25) and males (COMP = 76.57 ± 7.77), nor between participants with history of concussion (COMP = 75.83 ± 7.90) versus those never concussed (COMP = 76.75 ± 7.57).
Conclusion:
This study provides SOT reference values for young, healthy, active individuals, which will assist in the interpretation of individual scores for concussion diagnosis and recovery, as well as serve as baseline data for future studies. These data on 17-23-year-olds will add to the currently available normative values of 14-15-year-olds and 20-59-year-olds.
Level of evidence:
4.
Background
Like many physiologic processes, time-of-day may influence postural control and gait. A better understanding of diurnal variations in postural control and gait may help to improve diagnoses, reduce falls, and optimize rehabilitation and training routines. This review summarizes the current literature that addresses these questions.
Research Question
Does time-of-day affect postural control and gait?
Methods
We searched PubMed, Google Scholar, and IEEE using a combination of keyword and MeSH terms. We included papers that studied human subjects and assessed gait or postural control as a function of time-of-day. We evaluated the quality of the identified papers based on nine assessment criteria and analyzed them considering the topic (postural control or gait), age, and characteristics of the conducted assessments. We then quantitatively synthesized the results across studies using a meta-analytical approach (i.e., Hedges' g model).
Results
Twenty-two papers considered the relationship between time-of-day and postural control, and eleven considered the relationship between time-of-day and gait. Six studies found that postural control was best in the morning, four described postural control being best in the afternoon, four described optimal postural control in the evening, and eight reported no time-of-day effect. Two studies found gait best in the morning, five described gait best in the afternoon, two described optimal gait in the evening, and two reported no time-of-day effect. The results of the quantitative analysis suggest that both postural control and gait were best in the evening.
Significance
While there is no clear consensus on whether there is a time-of-day effect for postural control and gait, the findings of this review provide initial evidence suggesting that a small but statistically significant effect exists in favor of the evening. Standardized testing, including repeated and continuous evaluations, may help provide more definitive information on time-of-day influences on postural control and gait.
This study aimed to examine the reliability and the time-of-day variability on standing long jump (SLJ), three hop test (THT) speed (5-m, and 20-m sprint), and balance (Y balance test [Y-BT]) in prepuberal male soccer players. Data were gathered from two phases, using 105 soccer players. Reliability was investigated in phase 1. Time of day effect on SLJ, THT, 5-m, and 20-m speed and Y-BT tests was investigated in phase 2. Phase 1 showed non-significant bias between the two applications of the SLJ, THT, 5-m, and 20-m speed, and Y-BT tests . The SLJ, THT, 5-m, and 20-m speed, and Y-BT scores showed high relative and absolute reliability. The usefulness analysis showed that the SLJ, THT, 5-m and 20-m speed, and Y-BT tests could detect small changes in performance (SEM < SWC for all tests). Phase 2 showed that leg power, speed, and postural control are affected by time of day. A significantly better (p< 0.05) leg power, speed, and postural control were observed at the end of the afternoon than at morning hours. Time-of-day may be considered as a factor in designing leg power, speed, and postural control training programmes and intervention studies for prepuberal male soccer players.
[Purpose] The purpose of this study was to investigate the effect of time-of-day (early morning vs evening) on dynamic balance control using posturography and electromyography. [Participants and Methods] Nine healthy individuals participated in this study. They performed the Cross Test, moving the center of pressure (COP) laterally and longitudinally on a force plate with their eyes open and closed. The electromyograms (EMGs) from the anterior tibialis, and the medial and lateral gastrocnemius were simultaneously recorded. [Results] Compared with the evening, in the morning, the participants demonstrated decreased longitudinal COP sway when their eyes were closed, and increased EMG activity when their eyes were open. [Conclusion] In the morning, the participants showed significantly poorer performance in the dynamic balance test. Increased muscle activity in the morning might be due to compensation for reduced longitudinal sway.
[Purpose] We attempted to determine whether static and dynamic postural control ability fluctuated depending on the influence of the time of day (9 am, 1 pm, and 5 pm), and at which time point postural balance performance was best in healthy individuals. [Subjects and Methods] Twenty-four healthy subjects participated in this study. The static and dynamic postural balance test was conducted during three sessions (i.e., at 9 am, 1 pm, and 5 pm) with a counterbalanced order for prevention of learning effects. As outcome measurements, AP distance, ML distance, and velocity moment were adopted in the static balance test, and the performance time and total distance were measured in the dynamic balance test. [Results] For the static postural balance test, COP distance was shorter and COP velocity was slower at 9 am compared with those at 1 and 5 pm. In particular, the COP distance at 9 am was statistically different from that at 13 pm. During the dynamic postural balance test, performance time and total distance were influenced by the time of day, as the best performance was observed in the morning. [Conclusion] This study found that static and dynamic postural balance abilities were greatest in the morning and worst at 1 pm. Understanding of the mechanism of the time-of-day effect on postural balance will be helpful for assessment and treatment of postural balance by physical therapists and in making desirable clinical decisions.
Postural control deficits are associated with increased risk of loss of balance and potential injury. To assess balance deficits and estimate injury risk, there is a need to evaluate postural control during dynamic activities. Analysis during dynamic activities could assess if an individual's ability to control their posture is a fixed condition or if it is dependent on the demands of a task. The purpose of this study was to evaluate changes in postural control during a dynamic lower extremity task using time-to-contact (TtC) analysis. 3D motion capture with a force plate was used to evaluate 46 healthy recreational athletes performing an anterior reach with the right foot while standing on their left leg. TtC was calculated for nine valid trials. For each trial, the time from the toe leaving the force plate to the toe touching the floor at the maximum reach distance was divided into five epochs of equal duration. TtC was averaged over each epoch. Differences in TtC were evaluated with an unbalanced mixed effects ANOVA and post hoc Tukey's HSD comparisons. Epoch was a significant main effect (p<0.001), with both Epoch 4 and Epoch 5 having significantly greater TtC from all other epochs (p=0.05). Increasing TtC in later epochs suggests a higher demand for postural control when the task becomes more challenging. As an individual's reaching foot extends further from the body, postural control is adjusted to match the changing demands of the dynamic task.
Balance ability has been associated with performance and injury prevention in athletes. Few published reports have investigated the differences in dynamic balance abilities among male high school, collegiate, and professional soccer players.
To examine the differences on the Lower Quarter Y-Balance Test in male high school, collegiate, and professional soccer players.
Descriptive laboratory study.
Field testing. Patients or Other Participants: Dynamic balance data were collected for male high school (HS; n = 38), collegiate (n = 37), and professional (n = 44) soccer players during preparticipation physical examinations using the Lower Quarter Y Balance Test standardized protocol. Main Outcome Measure(s): For the Lower Quarter Y Balance Test, the participant reaches with 1 foot in the anterior, posteromedial, and posterolateral directions while standing on a centralized stance platform with the other foot. The test is performed for both left and right limbs. Differences in reach distances between competition levels were analyzed using a 1-way analysis of variance with significance set at P < .05. The HS group had a greater anterior reach distance than the other 2 groups. In contrast, the HS group had less reach distance in the posteromedial and posterolateral directions than the other groups. Also, HS players tended to exhibit a lower composite reach score than the other groups, but this difference was not significant (P = .08). No differences were observed among groups for bilateral symmetry in any of the reach directions.
Dynamic balance performance varied with competition level. This may indicate that athletes' movement strategies may be different depending on the competition level and that normative values may need to be established for each competition level.
Postural balance assessments are performed in both clinical and basic research settings on a daily basis. During a 24-h time span our physiology and physical performance undergo radical changes as we are influenced by the circadian rhythm. The time-of-day interaction on postural balance is unknown in older adults. The aim of this study was to investigate the time-of-day effect on postural balance in older adults.
Center of pressure (CoP) excursion was measured (100 Hz) by force plate analysis in 34 older adults during 30 s of narrow quiet bilateral stance. Measurements were performed around 9a.m., 12.30 p.m. and 4 p.m. on the same day. Postural balance was quantified by velocity-moment, confidence ellipse area, total sway area and total sway length.
An overall significant time-of-day (between 9 a.m. and 4 p.m.) effect was observed for velocity-moment (mm(2)/s) 57 ± 27-65 ± 29 (p = 0.001), confidence ellipse area (mm(2)) 36 ± 16-44 ± 19 (p < 0.001), total sway area (mm(2)) 548 ± 263-627 ± 285 (p = 0.001) and total sway length (mm) 373 ± 120-379 ± 113 (p = 0.037). The variation of postural balance was mostly pronounced from midday (12.30 p.m.) toward the afternoon (4 p.m.) in all sway parameters. Specifically between 12.30 p.m. and 4 p.m. confidence ellipse area increased by 18.5%, total sway area by 17.1%, velocity-moment by 15.8% and total sway length by 4.6%. No differences were observed between 9 a.m. and 12.30 p.m. in any of the sway parameters.
This study demonstrates that time-of-day influences postural balance in older adults. These findings have important scientific and clinical relevance, as they imply that time-of-day should be a controlled factor when assessing postural balance in older adults.
The inclusion of movement tests before performance training and sport participation is gaining popularity as part of musculoskeletal screening for injury. The identification of an athlete's asymmetries and poor performance in the preseason allows coaches and sports medicine clinicians the opportunity to proactively address these deficits to reduce the potential for injury. Currently, there are no tests reported in the literature that simultaneously require shoulder and core stability while taking the subjects through a large range of motion at the end range of their stability. Thus, the purpose of this article was to describe the Upper Quarter Y Balance Test and report the gender differences in the performance of the test. Upper extremity reach distances were measured in 95 active adults using a standardized upper extremity balance-and-reach protocol. Intraclass correlation coefficients were used to assess reliability, and gender differences were analyzed using an independent samples t-test, whereas bilateral differences were analyzed using a dependent samples t-test for the normalized composite reach scores. Intraclass correlation coefficient (3.1) for test-retest reliability ranged from 0.80 to 0.99. Intraclass correlation coefficient (3.1) for interrater reliability was 1.00. Average composite scores (right/left) reported as a percentage of limb length were 81.7/82.3% for men and 80.7/80.7% for women. The results of the study suggest that the Upper Quarter Y Balance Test is a reliable test for measuring upper extremity reach distance while in a closed-chain position. It was further determined that there was no significant difference in performance between genders or between sides on the test when normalized to limb length. Coaches and sports medicine professionals may consider incorporating the Upper Quarter Y Balance Test as part of their preprogram testing to identify movement limitations and asymmetries in athletes and thereby may reduce injury.
The Star Excursion Balance Test (SEBT) is a dynamic test that requires strength, flexibility, and proprioception and has been used to assess physical performance, identify chronic ankle instability, and identify athletes at greater risk for lower extremity injury. In order to improve the repeatability in measuring components of the SEBT, the Y Balance Test™ has been developed.
The purpose of this paper is to report the development and reliability of the Y Balance Test™.
Single limb stance excursion distances were measured using the Y Balance Test™ on a sample of 15 male collegiate soccer players. Intraclass Correlation Coefficients (ICC) were used to determine the reliability of the test.
The ICC for intrarater reliability ranged from 0.85 to 0.91 and for interrater reliability ranged from 0.99 to 1.00. Composite reach score reliability was 0.91 for intrarater and 0.99 for interrater reliability.
This study demonstrated that the Y Balance Test™ has good to excellent intrarater and interrater reliability. The device and protocol attempted to address the common sources of error and method variation in the SEBT including whether touch down is allowed with the reach foot, where the stance foot is aligned, movement allowed of the stance foot, instantaneous measurement of furthest reach distance, standard reach height from the ground, standard testing order, and well defined pass/fail criteria.
The Y Balance Test™ is a reliable test for measuring single limb stance excursion distances while performing dynamic balance testing in collegiate soccer players.
Jump landing is a common activity in collegiate activities, such as women's basketball, volleyball, and soccer, and is a common mechanism for anterior cruciate ligament (ACL) injury. It is important to better understand how athletes returning to competition after ACL reconstruction are able to maintain dynamic postural control during a jump landing.
To use time to stabilization (TTS) to measure differences in dynamic postural control during jump landing in ACL-reconstructed (ACLR) knees compared with healthy knees among National Collegiate Athletic Association Division I female athletes.
Case-control study.
University athletic training research laboratory.
Twenty-four Division I female basketball, volleyball, and soccer players volunteered and were assigned to the healthy control group (n = 12) or the ACLR knee group (n = 12). Participants with ACLR knees were matched to participants with healthy knees by sport and by similar age, height, and mass.
At 1 session, participants performed a single-leg landing task for both limbs. They were instructed to stabilize as quickly as possible in a single-limb stance and remain as motionless as possible for 10 seconds.
The anterior-posterior TTS and medial-lateral TTS ground reaction force data were used to calculate resultant vector of the TTS (RVTTS) during a jump landing. A 1-way analysis of variance was used to determine group differences on RVTTS. The means and SDs from the participants' 10 trials in each leg were used for the analyses.
The ACLR group (2.01 ± 0.15 seconds, 95% confidence interval [CI] = 1.91, 2.10) took longer to stabilize than the control group (1.90 ± 0.07 seconds, 95% CI = 1.86, 1.95) (F(1,22) = 4.28, P = .05). This result was associated with a large effect size and a 95% CI that did not cross zero (Cohen d = 1.0, 95% CI = 0.91, 1.09).
Although they were Division I female athletes at an average of 2.5 years after ACL reconstruction, participants with ACLR knees demonstrated dynamic postural-control deficits as evidenced by their difficulty in controlling ground reaction forces. This increased TTS measurement might contribute to the established literature reflecting differences in single-limb dynamic control. Clinicians might need to focus rehabilitation efforts on stabilization after jump landing. Further research is needed to determine if TTS is a contributing factor in future injury.
Athletes who return to sport participation after anterior cruciate ligament reconstruction (ACLR) have a higher risk of a second anterior cruciate ligament injury (either reinjury or contralateral injury) compared with non-anterior cruciate ligament-injured athletes.
Prospective measures of neuromuscular control and postural stability after ACLR will predict relative increased risk for a second anterior cruciate ligament injury.
Cohort study (prognosis); Level of evidence, 2.
Fifty-six athletes underwent a prospective biomechanical screening after ACLR using 3-dimensional motion analysis during a drop vertical jump maneuver and postural stability assessment before return to pivoting and cutting sports. After the initial test session, each subject was followed for 12 months for occurrence of a second anterior cruciate ligament injury. Lower extremity joint kinematics, kinetics, and postural stability were assessed and analyzed. Analysis of variance and logistic regression were used to identify predictors of a second anterior cruciate ligament injury.
Thirteen athletes suffered a subsequent second anterior cruciate ligament injury. Transverse plane hip kinetics and frontal plane knee kinematics during landing, sagittal plane knee moments at landing, and deficits in postural stability predicted a second injury in this population (C statistic = 0.94) with excellent sensitivity (0.92) and specificity (0.88). Specific predictive parameters included an increase in total frontal plane (valgus) movement, greater asymmetry in internal knee extensor moment at initial contact, and a deficit in single-leg postural stability of the involved limb, as measured by the Biodex stability system. Hip rotation moment independently predicted second anterior cruciate ligament injury (C = 0.81) with high sensitivity (0.77) and specificity (0.81).
Altered neuromuscular control of the hip and knee during a dynamic landing task and postural stability deficits after ACLR are predictors of a second anterior cruciate ligament injury after an athlete is released to return to sport.
This study assessed the validity of the Balance Scale by examining: how Scale scores related to clinical judgements and self-perceptions of balance, laboratory measures of postural sway and external criteria reflecting balancing ability; if scores could predict falls in the elderly; and how they related to motor and functional performance in stroke patients. Elderly residents (N = 113) were assessed for functional performance and balance regularly over a nine-month period. Occurrence of falls was monitored for a year. Acute stroke patients (N = 70) were periodically rated for functional independence, motor performance and balance for over three months. Thirty-one elderly subjects were assessed by clinical and laboratory indicators reflecting balancing ability. The Scale correlated moderately with caregiver ratings, self-ratings and laboratory measures of sway. Differences in mean Scale scores were consistent with the use of mobility aids by elderly residents and differentiated stroke patients by location of follow-up. Balance scores predicted the occurrence of multiple falls among elderly residents and were strongly correlated with functional and motor performance in stroke patients.
Reproduced with permission of the Canadian Public Health Association.
Repeated measures (3 separate day sessions) to determine test reliability; single-session repeated measures to compare stability between limbs.
To develop a functional test measuring dynamic stability that is capable of differentiating between the injured and uninjured lower limb in 2 populations: (1) people with anterior cruciate ligament deficiency (ACLd) and (2) people with anterior cruciate ligament reconstruction (ACLr), and to establish the reliability of this test.
Many functional tests of the lower limb used by clinicians, such as the 1-legged hop for distance, the 1-legged hop for time, the vertical jump, the triple hop for distance, shuttle run, and single-limb standing, do not allow the clinician to discern differences between function in the injured and uninjured limbs.
Twenty-five nonimpaired subjects (14 men, 11 women, aged 31.2 +/- 9.1 years), 11 subjects with ACLr (9 men, 2 women, aged 26.3 +/- 10.4 years), and 13 subjects with ACLd (5 men, 8 women, aged 40.4 +/- 12.6 years) were tested. Twelve nonimpaired subjects participated in 3 testing sessions to determine the reliability of the force plate measures. Ground reaction forces (vertical, medial-lateral, and anterior-posterior) were measured while the subjects performed 1-legged hop and step-down tests onto a force plate. Stability was defined as the ability to transfer the vertical projection of the center of gravity to the supporting base and keep the knee still. A repeated-measures analysis of variance (2-factor; limbs by trials) was used to compare the stability between limbs.
The majority of the measures used to calculate dynamic stability were reliable. Moreover, the data provide normal standards of functional knee stability for step-down and hop tests. In the step-down test, changes in vertical force did identify dysfunction in the injured limb (stabilization time = 1527 +/- 216 ms) compared to the uninjured limb (stabilization time = 892 +/- 498 ms) for subjects with ACLr.
The normal standards may serve as a reference for comparing functional differences in ACLr or ACLd populations. The vertical force parameter during a step-down may be useful as an outcome measure to monitor progress during rehabilitation.
Ankle sprains are the most common injuries in a variety of sports.
A proprioceptive balance board program is effective for prevention of ankle sprains in volleyball players.
Prospective controlled study.
There were 116 male and female volleyball teams followed prospectively during the 2001-2002 season. Teams were randomized by 4 geographical regions to an intervention group (66 teams, 641 players) and control group (50 teams, 486 players). Intervention teams followed a prescribed balance board training program; control teams followed their normal training routine. The coaches recorded exposure on a weekly basis for each player. Injuries were registered by the players within 1 week after onset.
Significantly fewer ankle sprains in the intervention group were found compared to the control group (risk difference = 0.4/1000 playing hours; 95% confidence interval, 0.1-0.7). A significant reduction in ankle sprain risk was found only for players with a history of ankle sprains. The incidence of overuse knee injuries for players with history of knee injury was increased in the intervention group. History of knee injury may be a contraindication for proprioceptive balance board training.
Use of proprioceptive balance board program is effective for prevention of ankle sprain recurrences.
We discuss current knowledge on the description, impact, and underlying causes of circadian rhythmicity in sports performance. We argue that there is a wealth of information from both applied and experimental work, which, when considered together, suggests that sports performance is affected by time of day in normal entrained conditions and that the variation has at least some input from endogenous mechanisms. Nevertheless, precise information on the relative importance of endogenous and exogenous factors is lacking. No single study can answer both the applied and basic research questions that are relevant to this topic, but an appropriate mixture of real-world research on rhythm disturbances and tightly controlled experiments involving forced desynchronization protocols is needed. Important issues, which should be considered by any chronobiologist interested in sports and exercise, include how representative the study sample and the selected performance tests are, test-retest reliability, as well as overall design of the experiment.
New measures of dynamic postural stability are needed to address weaknesses of previous measures.
To assess the feasibility, reliability, and precision of a new measure of dynamic postural stability.
A single within-subjects design was used to determine optimal sampling interval as well as intersession reliability.
Biomechanics laboratory.
Eighteen subjects (7 men [age = 22 +/- 3 years, height = 175 +/- 5 cm, mass = 75 +/- 16 kg] and 11 women [age = 23 +/- 2 years, height = 163 +/- 6 cm, mass = 68 +/- 13 kg]) without lower extremity impairment.
A jump protocol that required subjects to perform a 2-legged jump to a height equivalent to 50% of their maximum vertical leap and land on a single leg.
The Dynamic Postural Stability Index (DPSI) and the directional components (medial-lateral, anterior-posterior, and vertical) after a jump landing.
We observed a significant sampling-interval main effect (F(2,51) = 26.88, P < .01) for the DPSI; the 10-second trial duration produced significantly smaller means than the 5- and 3-second trial durations, whereas the 5-second trial result was also significantly smaller than that of the 3-second trial. The DPSI was highly reliable between test sessions (intraclass correlation coefficient = .96) and very precise (SEM = .03).
These results suggest that the DPSI can be used in conjunction with a functional single-leg hop stabilization test and is a reliable and precise measure of dynamic postural stability. We believe the shortest sampling interval (3 seconds) is the best choice for studying and mimicking athletic performance as closely as possible.
Ankle sprains are the most common musculoskeletal injuries that occur in athletes, and they have a profound impact on health care costs and resources.
A balance training program can reduce the risk of ankle sprains in high school athletes.
Randomized controlled clinical trial; Level of evidence, 1.
Seven hundred and sixty-five high school soccer and basketball players (523 girls and 242 boys) were randomly assigned to either an intervention group (27 teams, 373 subjects) that participated in a balance training program or to a control group (28 teams, 392 subjects) that performed only standard conditioning exercises. On-site athletic trainers recorded athlete exposures and sprains.
The rate of ankle sprains was significantly lower for subjects in the intervention group (6.1%, 1.13 of 1000 exposures vs 9.9%, 1.87 of 1000 exposures; P = .04). Athletes with a history of an ankle sprain had a 2-fold increased risk of sustaining a sprain (risk ratio, 2.14), whereas athletes who performed the intervention program decreased their risk of a sprain by one half (risk ratio, 0.56). The ankle sprain rate for athletes without previous sprains was 4.3% in the intervention group and 7.7% in the control group, but this difference was not significant (P = .059).
A balance training program will significantly reduce the risk of ankle sprains in high school soccer and basketball players.
Prospective cohort.
To determine if Star Excursion Balance Test (SEBT) reach distance was associated with risk of lower extremity injury among high school basketball players.
Although balance has been proposed as a risk factor for sports-related injury, few researchers have used a dynamic balance test to examine this relationship.
Prior to the 2004 basketball season, the anterior, posteromedial, and posterolateral SEBT reach distances and limb lengths of 235 high school basketball players were measured bilaterally. The Athletic Health Care System Daily Injury Report was used to document time loss injuries. After normalizing for lower limb length, each reach distance, right/left reach distance difference, and composite reach distance were examined using odds ratio and logistic regression analyses.
The reliability of the SEBT components ranged from 0.82 to 0.87 (ICC3,1) and was 0.99 for the measurement of limb length. Logistic regression models indicated that players with an anterior right/left reach distance difference greater than 4 cm were 2.5 times more likely to sustain a lower extremity injury (P<.05). Girls with a composite reach distance less than 94.0% of their limb length were 6.5 times more likely to have a lower extremity injury (P<.05).
We found components of the SEBT to be reliable and predictive measures of lower extremity injury in high school basketball players. Our results suggest that the SEBT can be incorporated into preparticipation physical examinations to identify basketball players who are at increased risk for injury.
Assessment of postural control is used extensively in clinical and research applications. Time of day affects aspects of physical performance, but whether it also affects postural control is unknown.
To determine the influence of time of day on static and dynamic postural control.
For each static postural control variable, a separate 3-way (day, time, eye) repeated-measures analysis of variance (ANOVA) was performed. For the dynamic postural control variable, a 2-way (day, time) repeated-measures ANOVA was performed.
University research laboratory.
Thirty healthy college-aged subjects.
Static and dynamic postural control of each subject was assessed in a laboratory at 10:00, 15:00, and 20:00 on 2 consecutive days.
Unilateral static postural control was assessed with eyes open and closed on a forceplate using center-of-pressure velocity in the anterior-posterior and medial-lateral planes as the dependent variables. Dynamic postural control was assessed with the anterior reaching direction of the Star Excursion Balance Test using reach distances normalized to leg length as the dependent variable.
For static postural control, velocity scores in both directions were lower at 10:00 than at 15:00 and 20:00 on day 1 (P < .05). For dynamic postural control, normalized reach distance was greater at 10:00 than at 15:00 and 20:00 (P < .05).
Time of day had a consistent influence on dynamic postural control that suggests performance of this task may be better in the morning than in the afternoon or evening. The influence of time of day on static postural control was not as consistent and we feel requires further investigation. These findings have implications for researchers and clinicians when implementing and interpreting postural control testing.
Context
Functional ankle instability (FAI) is difficult to identify and quantify.
Objective
To compare joint position sense (JPS), time to stabilization (TTS), and electromy-ography (EMG) of ankle musculature in recreational athletes with and without FAI.
Design
Case-control compared with t tests and ANOVAs.
Setting
Sports medicine research laboratory.
Participants
20 recreational athletes.
Main Outcome Measures
Passive angle reproduction, TTS, and mean EMG amplitude of the tibialis anterior, peroneals, lateral gastrocnemius, and soleus muscles during single-leg-jump landing.
Results
No differences in JPS or medial-lateral TTS measures between groups. Significantly longer anterior-posterior TTS ( P < .05) in the unstable ankle group. The stable ankle group had significantly higher mean EMG soleus amplitude after landing ( P < .05). No other significant differences were found for mean EMG amplitudes before or after landing.
Conclusions
Subjects with FAI demonstrated deficits in landing stability and soleus muscle activity during landing that may represent chronic adaptive changes following injury.
Quality characteristics analyzed in statistical process control (SPC) often are required to be normally distributed. This is true in many types of control charts and acceptance sampling plans, as well as in process capability studies. If a characteristic is not normally distributed, but normal-based techniques are used, serious errors can result. One approach to solving this problem is to transform the non-normal data to normality using the Johnson system of distributions. In this paper, we use the sample quantile ratio, in conjunction with the Shapiro-Wilk test of normality, to find a suitable transformation for non-normal data. Examples of fitting non-normal SPC data are presented and discussed. The effect of the Johnson transformation on an SPC procedure involving an estimator for the population standard deviation is studied using non-normal data and Johnson-transformed data.
Background:
Anterior cruciate ligament injuries (ACL) commonly occur during jump landing and cutting tasks. Attempts to land softly and land with greater knee flexion are associated with decreased ACL loading. However, their effects on performance are unclear.
Hypothesis:
Attempts to land softly will decrease peak posterior ground-reaction force (PPGRF) and knee extension moment at PPGRF compared with a natural landing during stop-jump and side-cutting tasks. Attempts to land with greater knee flexion at initial ground contact will increase knee flexion at PPGRF compared with a natural landing during both tasks. In addition, both landing techniques will increase stance time and lower extremity mechanical work as well as decrease jump height and movement speed compared with a natural landing during both tasks.
Study design:
Controlled laboratory study.
Methods:
A total of 18 male and 18 female recreational athletes participated in the study. Three-dimensional kinematic and kinetic data were collected during stop-jump and side-cutting tasks under 3 conditions: natural landing, soft landing, and landing with greater knee flexion at initial ground contact.
Results:
Attempts to land softly decreased PPGRF and knee extension moment at PPGRF compared with a natural landing during stop-jump tasks. Attempts to land softly decreased PPGRF compared with a natural landing during side-cutting tasks. Attempts to land with greater knee flexion at initial ground contact increased knee flexion angle at PPGRF compared with a natural landing during both stop-jump and side-cutting tasks. Attempts to land softly and land with greater knee flexion at initial ground contact increased stance time and lower extremity mechanical work, as well as decreased jump height and movement speed during both stop-jump and side-cutting tasks.
Conclusion:
Although landing softly and landing with greater knee flexion at initial ground contact may reduce ACL loading during stop-jump and side-cutting tasks, the performance of these tasks decreased, as indicated by increased stance time and mechanical work as well as decreased jump height and movement speed.
Clinical relevance:
Training effects tested in laboratory environments with the focus on reducing ACL loading may be reduced in actual competition environments when the focus is on athlete performance. The effects of training programs for ACL injury prevention on lower extremity biomechanics in athletic tasks may need to be evaluated in laboratories as well as in actual competitions.
An increased knee abduction angle during jump-landing has been identified as a risk factor for anterior cruciate ligament injuries. Activation of the hip abductors may decrease the knee abduction angle during jump-landing. The purpose of this study was to examine the effects of a resistance band on the internal hip abduction moment and gluteus medius activation during the pre-landing (100 ms before initial contact) and early-landing (100 ms after initial contact) phases of a jump-landing-jump task. Thirteen male and 15 female recreational athletes (age: 21.1±2.4 yr; mass: 73.8±14.6 kg; height: 1.76±0.1 m) participated in the study. Subjects performed jump-landing-jump tasks with or without a resistance band applied to their lower shanks. During the with-band condition, subjects were instructed to maintain their movement patterns as performing the jump-landing task without a resistance band. Lower extremity kinematics, kinetics, and gluteus medius electromyography (EMG) were collected. Applying the band increased the average hip abduction moment during pre-landing (p<0.001, Cohen's d (d)=2.8) and early-landing (p<0.001, d=1.5), and the average gluteus medius EMG during pre-landing (p<0.001, d=1.0) and early-landing (p=0.003, d=0.55). Applying the band decreased the initial hip flexion angle (p=0.028, d=0.25), initial hip abduction angle (p<0.001, d=0.91), maximum knee flexion angle (p=0.046, d=0.17), and jump height (p=0.004, d=0.16). Applying a resistance band provides a potential strategy to train the strength and muscle activation for the gluteus medius during jump-landing. Additional instructions and feedback regarding hip abduction, hip flexion, and knee flexion may be required to minimize negative changes to other kinematic variables.
Back injury caused by sudden loading is a significant risk among workers that perform manual handling tasks. The present study investigated the effects of load handling position on trunk biomechanics (flexion angle, L5/S1 joint moment and compression force) during sudden loading. Eleven subjects were exposed to a 6.8 kg sudden loading while standing upright, facing forward and holding load at three different vertical heights in the sagittal plane or 45° left to the sagittal plane (created by arm rotation). Results showed that the increase of load holding height significantly elevated the peak L5/S1 joint compression force and reduced the magnitude of trunk flexion. Further, experiencing sudden loading from an asymmetric direction resulted in significantly smaller peak L5/S1 joint compression force, trunk flexion angle and L5/S1 joint moment than a symmetric posture. These findings suggest that handling loads in a lower position could work as a protective strategy during sudden loading.
Quality characteristics analyzed in statistical process control (SPC) often are required to be normally distributed. This is true in many types of control charts and acceptance sampling plans, as well as in process capability studies. If a characteristic is not normally distributed, but normal-based techniques are used, serious errors can result. One approach to solving this problem is to transform the non-normal data to normality using the Johnson system of distributions. In this paper, we use the sample quantile ratio, in conjunction with the Shapiro-Wilk test of normality, to find a suitable transformation for non-normal data. Examples of fitting non-normal SPC data are presented and discussed. The effect of the Johnson transformation on an SPC procedure involving an estimator for the population standard deviation is studied using non-normal data and Johnson-transformed data.
Unlabelled:
Sudden unexpected loading has been identified as a risk factor of work-related low back pain (LBP). This study investigated the effects of different foot placements and load-releasing locations on trunk biomechanics under an unexpected sudden loading event. Fifteen subjects experienced sudden release of a 6.8-kg external load from symmetric or asymmetric directions while maintaining four different foot placements. The results showed that subjects experienced on average 4.1° less trunk flexion, 6.6 Nm less L5/S1 joint moment and 32.0 N less shear force with staggered stance with the right foot forward (the most preferred placement) compared with wide stance (the least preferred placement). Asymmetric load-releasing positions consistently resulted in smaller impacts on trunk biomechanics than symmetric positions. The findings suggest that staggered stance and asymmetric load-holding position can be used as a protective load-handling posture against LBP caused by sudden loading.
Practitioner summary:
In a work environment, unexpected sudden loading may cause low back pain (LBP). In this study, we used empirical data to demonstrate how different foot placements and load-releasing locations can be used to mitigate the impact of sudden loading on the spine and to reduce the risk of LBP.
Abnormal movement patterns have been identified as important prospective risk factors for lower extremity injury, including ACL injury. Specifically, poor neuromuscular control during the early landing phase has been associated with increased injury risk. While it is commonly assumed that higher division collegiate athletes generally exhibit better movement patterns than lower division athletes, few studies compare biomechanical differences on basic tasks such as jump landing between various levels of athletic groups. This study's objective was to evaluate jump landing and fitness differences among college-aged Intramural, Competitive Club, and NCAA Division I level athletes. Two hundred and seventy-seven student-athletes, (222 males, 55 females; age 19.3±.8) categorized as NCAA Division I, Competitive Club, or Intramural level athletes were evaluated during a jump landing task using the Landing Error Scoring System (LESS), a validated, qualitative movement assessment. Fitness was measured using the Army Physical Fitness Test (APFT). Results showed no significant differences in landing errors between the levels of athletic group (F2, 267=.36, p = 0.70). There was a significant difference in landing errors between genders (F1, 268=3.99, p = 0.05). Significant differences in APFT scores were observed between level of athletic group (F2, 267=11.14, p<.001) and gender (F1, 268=9.27, p=0.003). There was no significant correlation between APFT and LESS scores (p = 0.26). In conclusion, higher level athletes had better physical fitness as measured by the APFT, but did not as a group exhibit better landing technique. The implications of this research suggest that "high risk" movement patterns are prevalent in all levels of athletes.
This article focuses on physical performances after training at a specific time of day. To date, although the effect of time of day on aerobic performances appears to be equivocal, during anaerobic exercises, the effect of time of day has been well established with early morning nadirs and peak performances in the late afternoon. These diurnal rhythms can be influenced by several factors such as the regular training at a specific time of day. Indeed, regular training in the morning hours may increase the lower morning performances to the same or even higher level as their normal diurnal peak typically observed in the late afternoon by a greater increase of performance in the evening. However, regular training in the evening hours may increase the morning-evening (i.e., amplitude of the rhythm) difference by a greater increase of performance in the late afternoon. Therefore, adaptations to training are greater at the time of day at which training is regularly performed than at other times. Nevertheless, although modifications in resting hormones concentrations could explain this time-of-day specific adaptations, precise information on the underlying mechanisms is lacking.
To examine the relationship and differences between static and dynamic postural stability in healthy, physically active adults.
Descriptive laboratory study.
Research laboratory.
Ten females (age: 21.6 ± 1.2 yrs, mass: 60.8 ± 7.6 kg, height: 165.0 ± 5.0 cm) and ten males (age: 25.1 ± 3.0 yrs, mass: 73.9 ± 8.7 kg, height: 173.5 ± 9.0 cm).
Static postural stability was measured during a single-leg standing task (standard deviation of the ground reaction forces). Dynamic postural stability was measured during a single-leg landing task using the Dynamic Postural Stability Index. Pearson's r-coefficients were calculated to examine relationships between the two tests and a one-way ANOVA was calculated to examine potential differences in test scores (p < 0.05).
None of the Pearson's r-coefficients achieved statistical significance. The one-way ANOVA and post hoc comparisons demonstrated that dynamic postural stability scores were significantly higher than static postural stability scores.
A lack of a correlation between static and dynamic measures and increase in difficulty during dynamic measures indicates differences in the type and magnitude of challenge imposed by the different postural stability tasks. The more challenging dynamic measures of postural stability may be more suitable for prospective studies examining risk of ankle and knee injury in healthy, physically active individuals.
The relationship between balance ability and sport injury risk has been established in many cases, but the relationship between balance ability and athletic performance is less clear. This review compares the balance ability of athletes from different sports, determines if there is a difference in balance ability of athletes at different levels of competition within the same sport, determines the relationship of balance ability with performance measures and examines the influence of balance training on sport performance or motor skills.
Based on the available data from cross-sectional studies, gymnasts tended to have the best balance ability, followed by soccer players, swimmers, active control subjects and then basketball players. Surprisingly, no studies were found that compared the balance ability of rifle shooters with other athletes. There were some sports, such as rifle shooting, soccer and golf, where elite athletes were found to have superior balance ability compared with their less proficient counterparts, but this was not found to be the case for alpine skiing, surfing and judo. Balance ability was shown to be significantly related to rifle shooting accuracy, archery shooting accuracy, ice hockey maximum skating speed and simulated luge start speed, but not for baseball pitching accuracy or snowboarding ranking points. Prospective studies have shown that the addition of a balance training component to the activities of recreationally active subjects or physical education students has resulted in improvements in vertical jump, agility, shuttle run and downhill slalom skiing. A proposed mechanism for the enhancement in motor skills from balance training is an increase in the rate of force development. There are limited data on the influence of balance training on motor skills of elite athletes. When the effectiveness of balance training was compared with resistance training, it was found that resistance training produced superior performance results for jump height and sprint time.
Balance ability was related to competition level for some sports, with the more proficient athletes displaying greater balance ability. There were significant relationships between balance ability and a number of performance measures. Evidence from prospective studies supports the notion that balance training can be a worthwhile adjunct to the usual training of non-elite athletes to enhance certain motor skills, but not in place of other conditioning such as resistance training. More research is required to determine the influence of balance training on the motor skills of elite athletes.
To assess the learning effect, test-retest reliability and measurement error associated with the SEBT.
Repeated-measures study.
Controlled university laboratory environment.
Twenty-two healthy recreational athletes (11 male age 22.3 ± 3.7 years, 11 female age 22.8 ± 3.1 years).
Repeated-measures ANOVA assessed learning affects. Intraclass correlations coefficients, standard error of measurement and smallest detectable difference values were calculated to assess reliability and measurement error.
Results showed that excursion distances stabilised after four trials, therefore trials five to seven were analysed for reliability. Test-retest reliability for all reach directions was high, with intraclass correlation coefficients ranging from 0.84 to 0.92. 95% confidence intervals, standard error of measurement and smallest detectable difference ranged from 77.84 to 94.00, 2.21-2.94% and 6.13-8.15%, respectively.
These statistics will allow clinicians to evaluate whether changes in SEBT scores are due to change in an individual's performance or random error. The findings of this study show that the SEBT is a reliable measure of lower limb function in healthy recreational athletes. Changes in normalised scores of at least 6-8% are needed to feel confident that a real change in SEBT performance has occurred.
Ankle sprain is a common injury in volleyball. Poor stabilometric performance (SP) is associated with high risks of sustaining ankle sprain. Balance training can improve SP and reduce ankle sprain, but no research has studied the effects of detraining on SP in highly trained athletes. The purpose of this study was to determine the effects of one-month postseason break on SP in female volleyball players. Eleven NCAA female volleyball players participated in two eye-closed single-leg stance tests before and after a one-month postseason break. Stance time, center of pressure (COP) area, COP standard deviation, and COP mean velocity were assessed during the tests. During the postseason break, subjects conducted self-selected exercise and the average training duration was 87% lower compared to the competition season. Subjects demonstrated significant increases in anterioposterior (A/P) COP standard deviation (1.6 +/- 0.4 vs. 1.8 +/- 0.4 cm, p = 0.05), mediolateral (M/L) COP velocity (6.5 +/- 1.5 vs. 7.1 +/- 1.3 cm/s, p = 0.05), and overall COP velocity (10.1 +/- 2.0 vs. 11.6 +/- 1.9 cm/s, p = 0.02) after postseason break. SP decreased in highly trained female volleyball players after one-month postseason break. The decrease in SP indicated a possible increased risk for ankle sprain injury.
Repeated measures designs have been widely employed in psychological experimentation, however, such designs have rarely been analyzed by means of permutation procedures. In the present paper certain aspects of hypothesis tests ina particular repeated measures design (one non-repeated factor (A) and one repeated factor (B) withK subjects per level ofA) were investigated by means of permutation rather than sampling processes. The empirical size and power of certain normal theoryF-tests obtained under permutation were compared to their nominal normal theory values. Data sets were established in which various combinations of kurtosis of subject means and intra-subject variance heterogeneity existed in order that their effect upon the agreement of these two models could be ascertained. The results indicated that except in cases of high intra-subject variance heterogeneity, the usualF-tests onB andAB exhibited approximately the same size and power characteristics whether based upon a permutation or normal theory sampling basis.
Stabilometry is an objective method used for studying postural equilibrium quantitatively. Stabilometric recordings were made in 127 soccer players to demonstrate functional instability of the ankle joint. The presence of previous ankle joint injuries, i.e., sprains or fractures, was documented. Reference values for stabilometry were obtained from a group of 30 normally-active non-soccer players without a history of injury to the ankle joint. A pathological stabilometric value was defined as one exceeding the mean value of the reference group by 2 SD. In players with a history of previous ankle joint injury no increased postural sway was found. On the other hand, players showing abnormal stabilometric values ran a significantly (P less than 0.001) higher risk of sustaining an ankle injury during the following season compared to players with normal values. Players with a history of previous ankle joint injury did not run a higher risk compared to players without previous injury. The findings indicate that an ankle joint injury did not result in a persistent functional instability; however, such instability did increase the risk of ankle joint injury.
The purpose of this study was to determine if a preseason measurement of balance while in a unilateral stance could predict susceptibility to ankle injury in a cohort of high school basketball players. Predicting risk for ankle injury could be important in helping to reduce the risk of these injuries and furthermore save health care costs.
Cohort study.
Data were collected at five high schools during the first 2 weeks of the 1997-1998 and 1998-1999 basketball seasons.
210 (119 male, age = 16.1 +/- 1.1 yr; height = 182.98 +/- 7.4 cm; weight = 76.4 +/- 10.9 kg; and 91 female, age = 16.3 +/- 1.3 yr; height = 170.9 +/- 7.8 cm; weight = 63.4 +/- 8.4 kg) high school basketball players who did not sustain a time loss ankle or knee injury within the previous 12 months served as subjects. Subjects did not use prophylactic ankle taping or bracing during the season.
Balance was quantified from postural sway scores measured while subjects performed unilateral balance tests with eyes both open and closed. Logistic regression analysis was carried out to determine if gender, dominant leg, and balance scores were related to ankle sprain injuries. In addition, Fischer's exact test was used to determine if the rate of ankle injuries was the same whether the subject had poor, average, or good balance. Balance was assessed by measuring postural sway with the NeuroCom New Balance Master version 6.0 (NeuroCom International, Clackamas, OR, U.S.A.). Testing to determine postural sway consisted of having subjects stand on one leg for three trials of 10 seconds with their eyes open, then repeated with their eyes closed. Subjects then underwent the same assessment while standing on the other leg. Postural sway was defined as the average degrees of sway per second (degrees S/S) for the 12 trials producing a compilation (COMP) score.
Ankle injury resulting in missed participation.
Subjects who sustained ankle sprains had a preseason COMP score of 2.01 +/- 0.32 (Mean +/- SD), while athletes who did not sustain ankle injuries had a score of 1.74 +/- 0.31. Higher postural sway scores corresponded to increased ankle sprain injury rates (p = 0.001). Subjects who demonstrated poor balance (high sway scores) had nearly seven times as many ankle sprains as subjects who had good balance (low sway scores) (p = 0.0002.)
In this cohort of high school basketball players, pre-season balance measurement (postural sway) served as a predictor of ankle sprain susceptibility.
To determine which combination of landing protocol and analysis technique would be the most effective at detecting differences in dynamic stability between healthy subjects and subjects with functional ankle instability (FAI).
Fifty-eight subjects participated in this investigation: 29 healthy individuals and 29 individuals with FAI. Subjects were assessed during a single test session for time to stabilization (TTS) in the anterior/posterior, medial/lateral, and vertical directions from two protocols: a step down and jump protocol. The step down protocol started with each subject atop a 20-cm-high platform, and the jump protocol started with subjects in a standing position 70 cm from the center of a force plate and required each subject to jump off both legs and touch a designated marker placed at a position equivalent to 50% of the subject's maximum vertical leap. TTS scores in the anterior/posterior, medial/lateral, and vertical direction were compared between group, protocol, and type of analysis.
A significant protocol by analysis by group interaction (F(1,56) = 6.9, P = 0.011) was observed for anterior/posterior TTS. Likewise, protocol by group (F(1,56) = 4.4, P = 0.042) and protocol by analysis (F(1,56) = 14.1, P < 0.001) interactions were also noted in anterior/posterior TTS. The jump protocol (2381.7 +/- 36.5 ms) produced significantly greater TTS scores in the vertical direction than the step protocol (1533.5 +/- 71.8 ms), whereas the unbounded third order polynomial (UTOP) method (2554.4 +/- 68.7 ms) produced significant greater TTS scores as compared with the sequential estimation (SE) method (1360.8 +/- 52.1 ms).
The jump protocol and UTOP method of analysis are the most effective TTS combination in detecting differences between healthy and FAI groups.
Traditionally, balance training has been used as part of the rehabilitation programme for ankle injuries. More recently, balance training has been adopted to try and prevent injuries to the ankle and knee joints during sport. The purpose of this review is to synthesise current knowledge in the area of balance ability, training and injury risk, highlight the findings and identify any future research needs. A number of studies have found that poor balance ability is significantly related to an increased risk of ankle injuries in different activities. This relationship appears to be more common in males than females. Multifaceted intervention studies that have included balance training along with jumping, landing and agility exercises have resulted in a significant decrease in ankle or knee injuries in team handball, volleyball and recreational athletes. It is unknown which component of the multifaceted intervention was most effective and whether the effects are additive. As a single intervention, balance training has been shown to significantly reduce the recurrence of ankle ligament injuries in soccer, volleyball and recreational athletes; however, it has not been clearly shown to reduce ankle injuries in athletes without a prior ankle injury. Balance training on its own has also been shown to significantly reduce anterior cruciate ligament injuries in male soccer players. Surprisingly, it was also found to be significantly associated with an increased risk of major knee injuries in female soccer players and overuse knee injuries in male and female volleyball players. The studies with the contrasting findings differed in aspects of their balance training programmes. It would appear that balance training, as a single intervention, is not as effective as when it is part of a multifaceted intervention. Research is required to determine the relative contribution of balance training to a multifaceted intervention so as to generate an effective and efficient preventative programme that can be adopted by athletes of most levels.
The effect of training at a specific time of day: A review
- H Chtourou
- N Souissi
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- J L Theiss
- J P Gerber
- K L Cameron
- A I Beutler
- S W Marshall
- L J Distefano
- C A Yunker
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