HPRC News Page

Suzanna Logan News

Summary

In her research, graduate student Suzanna Logan compared the ground reaction forces while running in the different types of shoes. Since the competitive footwear (i.e., flats and spikes) has much less cushioning than regular running shoes, there may be significant increases in the overall load on the body while running, which may play a role in injury risk. Future research could look at the effects of a plyometric training program on the ground reaction forces produced while running in competitive footwear.

Abstract:

To measure the differences in ground reaction forces between running shoes, racing flats, and distance spikes, twenty intercollegiate distance runners ran across a force plate at 6.7m/s (for males) and 5.74m/s (for females) in each of the three types of shoes. In order to control for differences in foot strike, only subjects who had a heel strike were included in the data analysis (n=16). Repeated-measures ANOVA and Tukey’s post-Hoc test (p<0.05) revealed impact peak to be significantly increased in the flats and spikes compared to running shoes. Loading rate and stiffness in spikes was significantly higher than in running shoes. Stance time in spikes and flats was decreased. These results can be used to better inform competitive runners, coaches, and trainers of the potential injury risks and performance benefits, when determining the frequency and duration of the use of competitive footwear in training.

Kevin Miller News

Summary

Graduate student Kevin C. Miller and Professor Kenneth L. Knight recently completed research examining Pain and Soreness Associated with a Percutaneous Electrical Stimulation Muscle Cramping Protocol. The research addresses the controversy among scientists concerning the best model for inducing muscle cramps. Electrical stimulation is said to be extremely painful, although no one has quantified this. This research is important because a reliable technique to induce muscle cramps would allow scientists to experiment with various treatments and prevention strategies as well as to better understand their etiology. The manuscript will be published in an upcoming issue of Muscle and Nerve.

Abstract:

Context: Muscle cramps are difficult to study scientifically. Scientists have attempted to induce them in a laboratory setting with various techniques such as exercise, magnetic stimulation, and electrical stimulation. Controversy exists regarding the best model for inducing muscle cramps. Electrical induction of muscle cramps is said to be extremely painful; no one has quantified the degree of pain. Objectives: (1) Quantify pain and soreness of a muscle cramping electrical stimulation protocol. (2) Determine how long soreness persists following cramp induction. (3) Determine if the technique can be altered to moderate pain and soreness. (4) Correlate pain and soreness with threshold frequency. (5) Compute reliability of measures. Design: A mixed-model ANOVA with repeated measures on time. Setting: Human performance laboratory. Patients or Other Participants: Twenty-three college students (10 men, 13 women: age = 21.41 ± 2.20 yrs, ht = 174.15 ± 10.61 cm, wt = 68.74 ± 10.13 kg). Interventions: Two cramps were induced in the dominant foots’ flexor hallicus brevis on 5 days either every day or every other day. Main Outcome Measure(s): An ungraduated 100 mm visual analog scale with anchors indicating no pain/soreness or worst pain/soreness was given before treatment, during treatment, 5 sec after treatment, and 30, 60, and 90 minutes post-cramp induction. The frequency (Hz) required for subjects to cramp, termed “threshold frequency” (TF) was also measured. Reliability was calculated using interclass correlation coefficients (ICC 3,1). Results: There were no differences between groups for pain (F_{1, 21} = .53, P = .48), soreness (F_{1, 21}= .83, P = .37), or TF (F_{1, 21} = .0002, P = .95). Therefore, the groups were condensed for subsequent analysis. Pain was mild (Day 1: 13.5 ± 15.2 mm; Days 2-5: ≤ 6.8 ± 9.72 mm on a 100 mm scale). Soreness was mild (Day 1: 8.5 ± 11.9, Days 2-5: ≤ 2.2 ± 3.4 mm on 100 mm scale), and returned to baseline within 30 mins. Threshold frequency did not increase until day 3 (P < .05). Pain and TF and soreness and TF were weakly correlated on all days (ranged from -.33 ≤ r ≥ .23). Intersession reliability was high (ICC 3,1 = .99). Conclusions: Electrical induction of cramps causes little pain or soreness; any residual soreness resolves within 30 mins. Scientists can induce cramps daily without fear of a cumulative effect on pain or soreness. We recommend one familiarization day prior to data collection to acclimate subjects to pain and soreness. Prior experience rather than TF may be the determining factor in the amount of pain or soreness experienced. Changes in measurements are due to scientific interventions rather than measurement variability. A reliable cramp induction technique will help scientists examine treatments, like pickle juice, for muscle cramps.