Brian M. Campbell

Effects of balance training on selected skills.

The purpose of this study was to determine the effect of a 4-week balance training program on specified functional tasks. Thirty-six subjects (age = 22.7 ± 2.10 years; height = 168.30 ± 9.55 cm; weight = 71.15 ± 16.40 kg) were randomly placed into control (C; n = 19) and experimental groups (Tx; n = 17). The Tx group trained using a commercially available balance training device (BOSU). Postural limits (displacement and sway) and functional task (time on ball, shuttle run, and vertical jump) were assessed during a pretest (T1), a posttest (T2), and 2 weeks posttraining (T3). Multivariate repeated measures analysis (a = 0.05) revealed significant differences in time on ball, shuttle run, total sway, and fore/aft displacement after the exercise intervention (T2). T3 assessment revealed that total sway and time on ball remained controlled; however, no other measures were retained. Balance training improved performance of selected sport-related activities and postural control measures, although it is unclear whether the effect of training would transfer to general functional enhancement.

Lower extremity muscle activation during baseball pitching.

Campbell, BM, Stodden, DF, and Nixon, MK. Lower extremity muscle activation during baseball pitching. J Strength Cond Res 24(4): 964-971, 2010-The purpose of this study was to investigate muscle activation levels of select lower extremity muscles during the pitching motion. Bilateral surface electromyography data on 5 lower extremity muscles (biceps femoris, rectus femoris, gluteus maximus, vastus medialis, and gastrocnemius) were collected on 11 highly skilled baseball pitchers and compared with individual maximal voluntary isometric contraction (MVIC) data. The pitching motion was divided into 4 distinct phases: phase 1, initiation of pitching motion to maximum stride leg knee height; phase 2, maximum stride leg knee height to stride foot contact (SFC); phase 3, SFC to ball release; and phase 4, ball release to 0.5 seconds after ball release (follow-through). Results indicated that trail leg musculature elicited moderate to high activity levels during phases 2 and 3 (38-172% of MVIC). Muscle activity levels of the stride leg were moderate to high during phases 2-4 (23-170% of MVIC). These data indicate a high demand for lower extremity strength and endurance. Specifically, coaches should incorporate unilateral and bilateral lower extremity exercises for strength improvement or maintenance and to facilitate dynamic stabilization of the lower extremities during the pitching motion.

Comparison of trunk kinematics in trunk training exercises and throwing.

Strength and conditioning professionals, as well as coaches, have emphasized the importance of training the trunk and the benefits it may have on sport performance and reducing the potential for injury. However, no data on the efficacy of trunk training support such claims. The purpose of this study was to examine the maximum differential trunk rotation and maximum angular velocities of the pelvis and upper torso of participants while they performed 4 trunk exercises (seated band rotations, cross-overs, medicine ball throws, and twisters) and compare these trunk exercise kinematics with the trunk kinematics demonstrated in actual throwing performance. Nine NCAA Division I baseball players participated in this study. Each participants trunk kinematics was analyzed while he performed 5 repetitions of each exercise in both dominant and nondominant rotational directions. Results indicated maximum differentiated rotation in all 4 trunk exercises was similar to maximum differentiated rotation (approximately 50-60°) demonstrated in throwing performance. Maximum angular velocities of the pelvis and upper torso in the trunk exercises were appreciably slower (approximately 50% or less) than the angular velocities demonstrated during throwing performance. Incorporating trunk training exercises that demonstrate sufficient trunk ranges of motion and velocities into a strength and conditioning program may help to increase ball velocity and/or decrease the risk injury.

Electromyography of 3 Scapular Muscles: A Comparative Analysis of the Cuff Link Device and a Standard Push-Up

CONTEXT The Cuff Link is a closed kinetic chain rehabilitation apparatus for the upper extremity. Limited research has established its effectiveness to elicit muscle activation of the scapular muscles. OBJECTIVE To determine if scapular muscle activation differs in response to 2 upper extremity closed kinetic chain exercises: Cuff Link and standard push-up. DESIGN A single-group, repeated-measures design. SETTING Controlled laboratory. PATIENTS OR OTHER PARTICIPANTS Twenty-eight healthy individuals (13 women: age = 19.69 +/- 1.55 years, height = 167.44 +/- 9.52 cm, mass = 61.00 +/- 8.79 kg; 15 men: age = 22.00 +/- 3.91 years, height = 181.44 +/- 6.60 cm, mass = 82.36 +/- 13.23 kg) with no history of shoulder or low back injury volunteered to participate in this study. INTERVENTION(S) Participants performed 10 trials of complete revolutions on the Cuff Link and 10 full-weight-bearing push-ups. We controlled trial velocity and randomized order. Trunk and shoulder positions were normalized to the participants height. Using surface electromyography, we recorded muscle activity of the serratus anterior, middle trapezius, and lower trapezius. Rectified and smoothed electromyography data for the serratus anterior, middle trapezius, and lower trapezius were normalized as a percentage of the maximal voluntary isometric contractions (%MVIC). MAIN OUTCOME MEASURE(S) Mean muscle activity of the serratus anterior, middle trapezius, and lower trapezius. We used paired-samples t tests to analyze the mean data for each condition. The alpha level was adjusted to .016 to avoid a type I error. RESULTS Middle trapezius %MVIC was greater during push-ups (27.01 +/- 20.40%) than during use of the Cuff Link (11.49 +/- 9.46%) (P = .001). Lower trapezius %MVIC was greater during push-ups (36.07 +/- 18.99%) than during use of the Cuff Link (16.29 +/- 8.64%) (P = .001). There was no difference in %MVIC for the serratus anterior between conditions. CONCLUSIONS The push-up demonstrated greater middle trapezius and lower trapezius activation levels compared with the Cuff Link. However, the push-up had a high participant failure rate. Because serratus anterior activation levels were similar, the Cuff Link may be an appropriate alternative for individuals lacking the upper body strength to perform a push-up.

Validity and reliability of a new test of upper body power.

Clemons, JM, Campbell, B, and Jeansonne, C. Validity and reliability of a new test of upper body power. J Strength Cond Res 24(6): 1559-1565, 2010-The purpose of this study was to determine the concurrent validity of a new bench press power (BPP) test using the medicine ball put (MBP) as the criterion measure. Forty-three college-age students (19 males and 24 females) participated in the study. Participants performed 1 repetition at maximum speed using 61.4 kg (males) and 25 kg (females), at a grip width of 130% of biacromial breadth. Timing was initiated manually at the moment of upward bar movement and stopped automatically as the bar broke an infrared beam 0.3 m above the chest. All tests were conducted within 2 weeks. There was 1 practice session for the BPP test and 2 separate testing sessions, one for BPP and the other for the MBP. Three BPP trials were separated by ≥2 minutes of passive recovery. Individual scores were the average of the second and third tests and were expressed in Watts: Power = Bar mass kg·9.81·0.3m/s. Medicine ball put scores were the average distance the ball was thrown on the second and third trials from a sitting position on a 45° recumbent weight bench. Concurrent validity was determined by conducting a Pearson Correlation on BPP and MBP scores at an alpha level of 0.05: males, r = 0.861; females, r = 0.79, (p < 0.000). In addition, results of an Intraclass R indicated excellent test-retest reliability for both males and females for BPP and the MBP (p < 0.05). The conclusion was that the BPP test is a logically and concurrently valid method for coaches and trainers to use in assessing upper body power for both college-age males and females.

Automated gait temporal–spatial assessment from non-motorized treadmill belt speed data

Non-motorized treadmills (NMT) provide belt speed data that can be used to estimate work output, and potentially, gait temporal-spatial parameters that provide an improved understanding of gait performance. The purpose of this study was to determine the validity of an automated technique that uses belt speed data from an NMT to estimate temporal-spatial gait parameters. Seventeen injury-free adult participants performed a series of 20-s, metronome-guided walking and running trials for each of eight predetermined cadence conditions (72-200 steps/min). Two NMT-based cadence algorithms [PSD estimated cadence (PEC) and threshold estimated cadence (TEC)], and one NMT-based step length algorithm (NMT_SL) were evaluated for their ability to predict traditional motion analysis-based measures of cadence and step length (MAC and MA_SL, respectively). The results of this study demonstrate that both the PEC and TEC algorithms were capable of predicting MAC with a standard error of the estimate (SEE) less than four steps/min (R(2) = 0.997 and R(2) = 0.993, respectively). Predictions of MA_SL from NMT_SL were separated by gait type (walking vs. running) to account for an obvious separation in the step length data with a qualitative gait change. When applied to walking data, NMT_SL was capable of predicting MA_SL with an SEE of 23 mm (R(2) = 0.96). When applied to running data, NMT_SL was capable of predicting MA_SL with an SEE of 44 mm (R(2) = 0.80). The assessment of the novel technique suggests that it is feasible to use non-motorized treadmill belt speed data to predict gait events and analyze simple gait metrics. Future research should evaluate the applicability of these algorithms for use with participants/patients presenting with pathological gait.

The Contribution of Trunk Axial Kinematics to Poststrike Ball Velocity During Maximal Instep Soccer Kicking.

To date, biomechanical analyses of soccer kicking have focused predominantly on lower-extremity motions, with little emphasis on the trunk and upper body. The purpose of this study was to evaluate differences in trunk axial kinematics between novice (n = 10) and skilled (n = 10) participants, as well as to establish the relationship of trunk axial motion and sagittal plane thigh rotation to poststrike ball velocity. Three-dimensional body segmental motion data were captured using high-resolution motion analysis (120 Hz) while each participant completed 5 maximal instep soccer-style kicks. The results demonstrate that skilled participants use 53% greater axial trunk range of motion compared with novice participants (P < .01), as well as 62% greater peak trunk rotation velocity (P < .01). The results also show a moderate, positive correlation of peak trunk rotation velocity with poststrike ball velocity (r = .57; P < .01), and peak hip flexion velocity with poststrike ball velocity (r = .63; P < .01). The current study highlights the potential for trunk rotation-specific training to improve maximum instep kick velocity in developing soccer athletes.

An Evaluation of Upper-Body Muscle Activation during Coupled and Uncoupled Instability Resistance Training.

Abstract Campbell, BM, Kutz, MR, Morgan, AL, Fullenkamp, AM, and Ballenger, R. An evaluation of upper-body muscle activation during coupled and uncoupled instability resistance training. J Strength Cond Res 28(7): 1833–1838, 2014—Recently, there has been a growth in the popularity of resistance exercises performed on unstable surfaces. However, the relationship between unstable surface training and load coupling on muscle activation is unclear. The purpose of this study was to evaluate changes in muscle activation during a barbell (BB) (coupled) and dumbbell (DB) (uncoupled) chest press exercise performed on an unstable surface. The 3 specific chest press conditions included 50% 1 repetition maximum (RM) with BB (50% BB), 50% 1RM with DBs (50% DB), and 25% 1RM with DBs (25% DB). Ten male subjects participated in the study (age, 23.9 ± 2.6 years; body weight, 82.8 ± 10.2 kg). During testing, mean electromyographic activity was assessed for pectoralis major (PM), triceps brachii, anterior deltoid (AD), and rectus abdominis (RA) and was presented as a percent change across the lifting conditions. It was observed that muscle activation increased by 15% in both the PM and RA from the 50% BB condition to the 50% DB condition. Also, the greatest percent difference in muscle activation between the 50 and 25% DB conditions occurred for PM and AD (+54% during 50% DB). These results suggest that demands on the core musculature to provide stability are increased with the use of DBs (uncoupled) as opposed to a BB (coupled). Where instability training provides a sufficient hypertrophy stimulus in prime mover muscle groups, there may be the added benefit of core stability training. Specifically, this type of training may benefit both untrained persons and those engaged in active rehabilitation.

A Comparison of Both Motorized and Nonmotorized Treadmill Gait Kinematics to Overground Locomotion

CONTEXT Motorized treadmills (MTs) present an altered motor task compared to overground (OG) locomotion in that MT belt surfaces are motor-driven, whereas individuals walking/running OG must propel themselves. A possible solution may lie with novel nonmotorized treadmill (NMT) devices as the belt surface is propelled by the user. OBJECTIVE The purpose of this study was to compare gait performance during both MT and NMT locomotion to OG. DESIGN Crossover study. SETTING A university research laboratory. PATIENTS A total of 20 healthy adults (10 women) participated in the study. INTERVENTION Each participant performed self-selected walking and running OG, and on both an MT and NMT. MAIN OUTCOME MEASURE Shoulder, trunk, and lower-extremity kinematics were analyzed for each treadmill condition and compared to OG. RESULTS The analyses demonstrated that there were no differences between MT and OG gait kinematics during either walking or running. However, NMT gait showed increased hip, knee, and ankle flexions in late swing and early stance compared to OG during both walking and running. For example, during walking, the NMT elicited hip-, knee-, and ankle-flexion/extension angles of 34.7°, 8.0°, and 3.6° at foot strike compared to 24.8°, -3.1°, and -5.8° in the OG condition (P < .05). There was also a significant reduction in trunk-flexion/extension range of motion during running compared to OG (7.7° in NMT vs 9.8° in OG). CONCLUSIONS These differences may have implications for both training and rehabilitation on an NMT. Future studies should consider the influence of NMT familiarization on gait performance and should emphasize the assessment of neuromuscular performance.

Effects of an Elastic Hamstring Assistance Device During Downhill Running

Abstract The purpose of this study was to determine the appropriateness of using an elastic hamstring assistance device to reduce perceived levels of soreness, increase isometric strength, increase passive range of motion, and decrease biomarkers of muscle damage after eccentric exercise, specifically, downhill running This study was conducted in a university exercise physiology laboratory placing sixteen apparently healthy males (X = 21.6 ± 2.5 years) into two groups using a pre-test/post-test design. Pre-intervention measures taken included participants’ body height, body mass, body fat, capillary blood samples, VO2max, isometric hamstring strength at 45 and 90 degrees of flexion and passive hamstring range of motion. Post-intervention measures included blood biomarkers, passive range of motion, the perceived level of soreness and isometric strength. An analysis of normality of data was initially conducted followed by multivariate analysis of variance (MANOVA) of hamstring strength at 45 and 90 degrees of flexion, blood myoglobin and passive range of motion of the hamstrings. Statistically significant changes were noted in subject-perceived muscle soreness and isometric strength at 90 degrees at the 24-hour post-exercise trial measure between the two groups. Results would suggest the findings could be explained by the decrease in muscle soreness from utilizing the device during the exercise trial. Further research should be conducted to address sample size issues and to determine if the results are comparable on different surfaces.