Open Access

Dynamic loading and kinematics analysis of vertical jump based on different forefoot morphology

  • Yang Shu1,
  • Yan Zhang2, 3, 4,
  • Lin Fu1,
  • Gusztáv Fekete3,
  • Julien S. Baker5,
  • Jianshe Li2 and
  • Yaodong Gu1, 2Email author
SpringerPlus20165:1999

https://doi.org/10.1186/s40064-016-3682-3

Received: 30 May 2016

Accepted: 14 November 2016

Published: 22 November 2016

Abstract

Purpose

This study examined differences in ankle motion and plantar pressure between habitually barefoot male (HBM) and habitually shod male (HSM) during vertical jump.

Methods

Eighteen habitually barefoot males and twenty habitually shod males volunteered to join the test. Distance between hallux and second toe was measured with Easy-Foot-Scan. Plantar pressure and ankle kinematics were measured with EMED force platform and Vicon motion analysis system respectively. T test was taken to analyse the significant differences using Stata 12.0 software.

Results

The distance between hallux and other toes in HBM was greater than it in HSM. HBM showed larger plantar loading under hallux and medial forefoot, while HSM showed lager plantar loading under medial and central forefoot. HBM had smaller ankle plantarflexion, eversion and external rotation than HSM.

Conclusion

Findings of this study provide basic information for further studies on different hallux/toe function in motion control between habitually shod and barefoot populations.

Keywords

Foot morphology Toes Vertical jump Plantar pressure

Background

Human is bipedal species using two feet to stand and move. Franklin et al. (2015) considered that human feet took the effort of balance and movement control. Morphological differences in foot could cause many foot malfunctions, disorders and deformity (Ledoux et al. 2003). Furthermore, foot morphology had a close relationship with areas: forefoot and toes have been reported to be the prominent target areas (Lambrinudi 1932; Rolian et al. 2009; Hoffmann 1905; D’AoÛt et al. 2009). Wolf et al. (2008) found that acquired behaviour such as footwear wearing may lead to foot structure deformation, such as flatfoot and hallux valgus. Toe separation of habitually barefoot populations showed to be more obvious compared with habitually shod populations (Wolf et al. 2008). In addition, previous studies indicated that habitually barefoot individuals were less likely to be injured than habitually shod ones during running (Robbins and Hanna 1987; Robbins et al. 1988). Lieberman et al. (2010) ascribed this difference to different foot strike patterns. Clinical research presented that metatarsal pathologies were more critical in habitually shod populations than in habitually barefoot populations (Zipfel and Berger 2007).

Jumping as a fundamental motion in sports frequently leads to lower limb injuries, primarily due to the rapid shock to lower limbs at landing (Vint and Hinrichs 1996; Doherty et al. 2014). Ankle sprain has been considered as one of the most common injuries in various sports with frequent jump motion such as volleyball, basketball and soccer. According to the survey, there are approximately 5600 incidences of ankle sprain per day in the UK, a mere between 3 and 5% of all Emergency Department visits (Pijnenburg et al. 2000). Larger plantar loading at forefoot and toes areas in take-off and landing may increase the risk of metatarsal injuries. However, whether there are differences in ankle motion and plantar loading between habitually barefoot populations and habitually shod populations in jumping remained to be unclear.

Therefore, the purpose of the study was to investigate difference in ankle kinematics and plantar pressure under forefoot and toes regions between habitually shod male (HSM) and barefoot male (HBM) during vertical jump based on different forefoot morphology. It was hypothesised that HBM and HSM would present different ankle motions (ankle variation angles and maximal or minimal angles) and plantar pressure characteristics related to different hallux and second toe separation.

Methods

Participants

Eighteen habitually barefoot males and twenty habitually shod males volunteered to join the test. All participants are Ningbo University students. The HBM come from South India, who are accustomed to walking and exercising barefoot or with slippers/flip-flops since born in daily life. The HSM are accustomed to wearing different kind of shoes since born in daily life. Basic information of participants is listed in Table 1. The Ethics Committee of Ningbo University approved this study (No. 2016FS021) and participants were informed of experiment procedures and requirements with obtained consent. They were free from injury or surgery of their lower extremity in the past six months. Easy-Foot-Scan (EFS), OrthoBaltic (Kaunas, Lithuania) was used to measure forefoot morphological difference of the minimal distance between hallux and the second toes. The minimal distance of HSM was smaller than the distance of HBM (Fig. 1a, b; HSM: 6.28 ± 1.42 mm, HBM: 23.75 ± 2.09 mm, P < 0.001 through the independent-samples T test).
Table 1

Descriptive statistics for age, height, mass, and foot length

 

Habitually barefoot males (N = 18)

Mean (SD)

Habitually shod males (N = 20)

Mean (SD)

Age (years)

24 ± 1.2

24 ± 2.1

Height (cm)

165.3 ± 1.2

172.1 ± 1.6

Mass (kg)

65.4 ± 6.9

66.2 ± 6.5

BMI (kg/m2)

23.88 ± 0.93

22.31 ± 1.97

Right leg length (cm)a

86.5 ± 2.8

89.3 ± 3.9

Right feet length (cm)

25.5 ± 1.4

25.5 ± 0.9

SD standard deviation

aRight leg length measurement from right anterior superior iliac spine to medial malleolus

Fig. 1

Foot of habitual shod subject (a), foot of habitual barefoot subject (b) and anatomical parts of plantar pressure (c)

Experiment procedure

An 8-camera Vicon motion analysis system (Oxford Metrics Ltd., Oxford, UK) was used to collect three-dimensional kinematic data at a frequency of 200 Hz. Participants were required to wear tight shorts. 16 reflective points (diameter 14 mm) were attached on different key locations of right and left lower extremity respectively including anterior–superior iliac spine, posterior–superior iliac spine, lateral mid-thigh, lateral knee, lateral mid-shank, lateral malleolus, second metatarsal head and calcaneus (Fig. 2). Kinetic data were recorded at 50 Hz using an EMED pressure plate (Novel, Germany). All participants were asked to land with forefoot region with right foot on the force plate. The forefoot region was divided into five anatomical parts: medial forefoot (MF), central forefoot (CF), lateral forefoot (LF), hallux (H), other toes (OT) (Fig. 1c). Peak pressure, contact area and pressure–time integral were used to analyse the difference between participants during take-off and landing phase.
Fig. 2

Marker set of three-dimensional kinematic data collection (a = side, b = front, c = rear)

Before test, each participant was required to warm up for 5 min. Then participants performed countermovement jump from a suitable pre-squatting motion under barefoot condition. Participants were required to keep their hands on hips in every vertical jump to reduce the energy through the torso activities. Each participant performed five trials, with resting 30 s to avoid fatigue.

Vertical jump height was calculated by the time of flight using Vicon motion analysis system with the formula (Bosco et al. 1983):
$${\text{Jump}}\;{\text{height}}\;\left( {\text{m}} \right) = \frac{{9.80\;{\text{m}}\;{\cdot}\;{\text{s}}^{ - 2} \times {\text{flight time}}\;\left( {\text{s}} \right)^{2} }}{8}$$

Data for analysis were extracted during the taking-off and landing phase. Take-off phase is defined as the period from knee joint starting to flexion to the foot taking off the ground. The instant of take-off is defined as the moment that the vertical ground reaction force closing to 0 N. Landing phase is defined as the period from the foot touching the ground to total knee extension. The instant of landing is defined as the moment that the vertical reaction force higher than 0 N.

Statistical analysis

All statistical analyses were performed using Stata 12.0 software. The t-test was taken to analysis the significance of jump height, ankle variation range, peak pressure, contact area and pressure–time integral. Significance level P < 0.05 is defined as statistical difference.

Result

There were no significant differences found in jump height between HBM and HSM (HBM: 0.39 ± 0.11 m; HSM: 0.40 ± 0.13 m, P > 0.05).

Ankle joints had significant differences between HBM and HSM during take-off phase (Fig. 3a) and landing phase (Fig. 3b). During take-off phase, ankle of HSM showed significantly larger peak dorsiflexion, eversion and external rotation than HBM. During landing phase, ankle of HSM showed significantly larger peak dorsiflexion, eversion and external rotation than those of HBM.
Fig. 3

The ankle joints angle curve of the ankle in three planes (sagittal, frontal and horizontal) (a = take-off phase, b = landing phase, Asterisk indicates a statistically significant difference between two groups, P < 0.05)

Table 2 presents comparison of ankle variation angles range during two phases between HSM and HBM. During take-off phase, angle variation range of HBM showed significantly smaller dorsi–plantar flexion and ev-inversion than that of HSM (dorsi–plantar flexion: P < 0.001, ev-inversion: P < 0.001). During landing phase, angle variation ranges of HBM showed significantly smaller dorsi–plantar flexion and ev-inversion angle than that of HSM (dorsi–plantar flexion: P < 0.001, ev-inversion: P < 0.001).
Table 2

Comparison of ankle variation range during two phases between HSM and HBM (mean ± SD)

 

Take-off phase

Landing phase

HBM

HSM

HBM

HSM

Dorsi–plantar flexion

60.85 ± 1.43*

68.25 ± 2.80*

42.45 ± 2.14*

60.40 ± 7.02*

Ev-inversion

3.16 ± 1.49*

6.96 ± 1.49*

3.29 ± 0.34*

6.19 ± 1.49*

gInt-external rotation

20.24 ± 2.47

22.36 ± 6.74

20.00 ± 1.33

18.66 ± 4.67

* Significant different between two groups, P < 0.05

At the moment of take-off, HBM showed significantly larger plantarflexion than that of HSM (P < 0.001). HBM showed to be inversion while HSM showed to be eversion at this moment (P < 0.001). HBM showed significantly smaller external rotation than HSM (P < 0.001). At the moment of landing, HBM showed significantly smaller eversion and external rotation than HSM (eversion: P < 0.001, external rotation: P < 0.001).

Table 3 and Fig. 4 present comparison of peak pressure, contact area and pressure–time integral between HBM and HSM. During take-off phase, for pressure–time integral, significant differences were found between HBM and HSM in H, MF and CF. HBM showed higher pressure–time integral than HSM in H (P < 0.001). However, the HSM showed greater pressure–time integral than HBM in MF and CF (MF: P = 0.0347; CF: P < 0.001). For peak pressure, significant differences were found in H, MF and CF. HBM showed higher peak pressure than HSM in H (P < 0.001). However, HSM showed higher peak pressure than HBM in MF and CF (MF: P < 0.001; CF: P < 0.001). For contact area, the HBM showed larger contact area than HSM in MF (P = 0.0082).
Table 3

Comparison of plantar pressure between HBM and HSM (mean ± SD)

 

Take-off phase

Landing phase

HBM

HSM

HBM

HSM

Pressure–time integral (Kpa*s)

 H

54.88 ± 15.26*

34.50 ± 11.76*

40.57 ± 7.74*

32.71 ± 11.09*

 OT

20.54 ± 5.10

22.70 ± 8.03

19.40 ± 4.41

21.01 ± 3.89

 MF

39.36 ± 8.77*

47.75 ± 14.71*

33.50 ± 3.20*

37.07 ± 4.76*

 CF

18.59 ± 6.14*

27.66 ± 10.81*

21.47 ± 7.46*

27.43 ± 9.50*

 LF

13.02 ± 1.56

13.83 ± 4.53

15.11 ± 1.24*

17.25 ± 4.44*

Peak pressure (Kpa)

 H

649.50 ± 260.09*

267.86 ± 69.11*

391.88 ± 188.61*

287.14 ± 71.07*

 OT

248.30 ± 86.50

242.14 ± 37.70

219.38 ± 68.13

207.14 ± 66.16

 MF

393.50 ± 135.44*

552.14 ± 241.49*

295.63 ± 123.74

295.00 ± 84.23

 CF

138.50 ± 71.36*

242.14 ± 124.66*

138.13 ± 53.76*

221.43 ± 88.43*

 LF

85.00 ± 44.32

102.86 ± 52.83

101.88 ± 35.19*

128.58 ± 54.75*

Contact area (cm2)

 H

8.88 ± 1.67

8.40 ± 0.80

7.53 ± 2.04

7.02 ± 2.05

 OT

8.57 ± 1.80

8.69 ± 1.43

6.94 ± 1.67*

5.57 ± 0.46*

 MF

13.98 ± 1.72*

12.45 ± 1.75*

13.29 ± 1.70

12.83 ± 1.50

 CF

15.58 ± 2.79

14.13 ± 5.95

17.25 ± 2.37*

20.87 ± 2.14*

 LF

8.79 ± 3.49

7.43 ± 3.89

11.43 ± 3.33

11.13 ± 1.15

* Significant different between two groups, P < 0.05

Fig. 4

The average peak pressure under forefoot and toes regions during take-off and landing phase. “Red square” indicated a significant difference between HSM and HBM

During landing phase, for pressure–time integral, significant differences were found between HBM and HSM in H, MF, CF and LF. HBM showed higher pressure–time integral than HSM in H (P = 0.0132), while HSM showed higher pressure–time integral than HBM in MF, CF and LF (MF: P = 0.0083; CF: P = 0.0335; LF: P = 0.0447). For peak pressure, significant differences were found in H, CF and LF. HBM showed higher peak pressure than HSM in H (P = 0.0075). HSM showed higher peak pressure than HBM in CF and LF (CF: P < 0.001; LF: P = 0.0256). For contact area, significant differences were found in OT and CF. HBM showed larger contact area than HSM in OT (P = 0.0011). HSM showed larger contact area than HBM in CF (CF: P < 0.001).

Discussion

Previously published researches have proved forefoot morphological difference between HBM from India and HSM from China that HBM have more obvious hallux and the second toe separation compared with HSM (Shu et al. 2015; Mei et al. 2015). This study verified differences in ankle kinematics and plantar loading between the two populations in vertical jump. HBM presented significantly larger plantar loading than HSM under hallux, which may be associated with the fact that hallux of HBM was significantly separate from other toes (Ashizawa et al. 1997). Differences in ankle motions also showed significance between HBM and HSM. However, no significant difference in jump height between two groups was observed.

During take-off phase, significant differences in pressure–time integral and peak pressure between HBM and HSM were under plantar regions of H, MF and CF. During landing phase, differences existed under hallux and forefoot. In this case, it further concluded that plantar loading of HBM was large under H and MF, while the pressure of HSM was large under MF and CF. Previous findings in relation to barefoot running suggested that HBM have distinctive features in push-off phase, which may be caused by the more separated toes of this population that could expand and firm the supporting base in gripping (Hoffmann 1905; Wolf et al. 2008; Ku et al. 2012). Since HBM used hallux while HSM used forefoot primarily during take-off, the significantly larger plantarflexion of HBM than HSM could be explained partly. Similarly, the larger ankle variation range of ev-inversion and int-external rotation of HSM conformed to kinetic results that peak pressure of HSM tended to shift laterally compared with HBM. Moreover, Salinero et al. stated that although increased ankle dorsiflexion could affect muscle activation, it would not improve jump performance (Salinero et al. 2014). This is consistent with the result in this study that HBM and HSM showed comparable jump height with different ankle position in the sagittal plane.

During landing phase, HBM showed larger plantarflexion but smaller eversion and external rotation than HSM. These were in line with the kinetic results that HBM showed larger peak pressure under hallux while smaller pressure under central and lateral forefoot. This suggested different functions of the hallux in motion control between HBM and HSM. Mei et al. (2015) also reported larger loading under the hallux among HBM during running, which may reduce impact force to forefoot area.

Ankle sprain is a common lower limb injury in sports, especially during landing phase in jump. Foot rotation has been reported as a principal factor for ankle sprain in clinical literature (Hopkinson et al. 1990). Previous studies have demonstrated that ankle injuries are associated with combined ankle motions of dorsiflexion, eversion and external rotation (Williams et al. 2007; Taylor and Bassett 1993; Wolfe et al. 2001). In this study, HBM showed smaller eversion and external rotation than HSM, indicating that HBM are at lower risk of ankle sprain compare with HSM (Rolian et al. 2009; Robbins and Hanna 1987). On the other hand, Novacheck (1998) and Tam et al. (2014) stated that excessive loading under metatarsal heads would lead to forefoot injuries such as metatarsal fracture. The larger peak pressure under metatarsal heads areas (MF, CF and LF) of HSM observed in this study indicated a higher risk of forefoot injuries among this population.

Conclusion

HBM and HSM showed different ankle motions and plantar loading in vertical jump, which is potentially due to forefoot morphological difference in the distance between hallux and the second toe. HBM showed larger ankle plantarflexion with smaller eversion and external rotation compared with HSM. Additionally, HBM showed larger plantar loading under hallux and medial forefoot, while HSM showed larger plantar loading under medial and central forefoot. Findings of this study provide basic information for further studies on different hallux/toe function in motion control between habitually shod and barefoot populations.

Declarations

Authors’ contributions

YS, YZ and LF collected all data, YS, JB, JL and YG drafted the manuscript. YS, GF and YZ performed the statistical analyses, YS, YZ and YG participated in the design and coordination and helped drafting the manuscript. All authors read and approved the final manuscript.

Acknowledgements

This study sponsored by Zhejiang Social Science Program ‘Zhi Jiang youth project’ (16ZJQN021YB), National Natural Science Foundation of China (81301600), K. C. Wong Magna Fund in Ningbo University, National Social Science Foundation of China (16BTY085), Loctek Ergonomic Technology Corp, and Anta Sports Products Limited.

Competing interests

The authors declare that they have no competing interests.

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors’ Affiliations

(1)
Faculty of Sports Science, Ningbo University
(2)
Research Academy of Grand Health Interdisciplinary, Ningbo University
(3)
Department of Mechanical Engineering, University of West Hungary
(4)
Department of Automation, Biomechanics and Mechatronics, The Lodz University of Technology
(5)
School of Science and Sport, University of the West of Scotland

References

  1. Ashizawa K, Kumakura C, Kusumoto A, Narasaki S (1997) Relative foot size and shape to general body size in Javanese, Filipinas and Japanese with special reference to habitual footwear types. Ann Hum Biol 24(2):117–129View ArticlePubMedGoogle Scholar
  2. Bosco C, Luhtanen P, Komi PV (1983) A simple method for measurement of mechanical power in jumping. Eur J Appl Physiol 51:129–135View ArticleGoogle Scholar
  3. D’AoÛt K, Pataky TC, De Clercq D, Aerts P (2009) The effects of habitual footwear use: foot shape and function in native barefoot walkers. Footwear Sci 1(2):81–94View ArticleGoogle Scholar
  4. Doherty C, Delahunt E, Caulfield B, Hertel J, Ryan J, Bleakley C (2014) The incidence and prevalence of ankle sprain injury: a systematic review and meta-analysis of prospective epidemiological studies. Sports Med 44(1):123–140View ArticlePubMedGoogle Scholar
  5. Franklin S, Grey MJ, Heneghan N, Bowen L, Li FX (2015) Barefoot vs common footwear: a systematic review of the kinematic, kinetic and muscle activity differences during walking. Gait Posture 42(3):230–239View ArticlePubMedGoogle Scholar
  6. Hoffmann P (1905) Conclusions drawn from a comparative study of the feet of barefooted and shoe-wearing peoples. Am J Orthop Surg 2(3):105–136Google Scholar
  7. Hopkinson WJ, Pierre PS, Ryan JB, Wheeler JH (1990) Syndesmosis sprains of the ankle. Foot Ankle Int 10(6):325–330View ArticleGoogle Scholar
  8. Ku PX, Abu Osman NA, Yusof A, Wan AW (2012) The effect on human balance of standing with toe-extension. PLoS ONE 7(7):e41539ADSView ArticlePubMedPubMed CentralGoogle Scholar
  9. Lambrinudi C (1932) Use and abuse of toes. Postgrad Med J 8(86):459View ArticlePubMedPubMed CentralGoogle Scholar
  10. Ledoux WR, Shofer JB, Ahroni JH, Smith DG, Sangeorzan BJ, Boyko EJ (2003) Biomechanical differences among pes cavus, neutrally aligned, and pes planus feet in subjects with diabetes. Foot Ankle Int 24(11):845–850PubMedGoogle Scholar
  11. Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D’Andrea S, Davis IS, Pitsiladis Y (2010) Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature 463(7280):531–535ADSView ArticlePubMedGoogle Scholar
  12. Mei Q, Fernandez J, Fu W, Feng N, Gu Y (2015) A comparative biomechanical analysis of habitually unshod and shod runners based on a foot morphological difference. Hum Mov Sci 42:38–53View ArticlePubMedGoogle Scholar
  13. Novacheck TF (1998) The biomechanics of running. Gait Posture 7(1):77–95View ArticlePubMedGoogle Scholar
  14. Pijnenburg AC, Van Dijk CN, Bossuyt PM, Marti RK (2000) Treatment of ruptures of the lateral ankle ligaments: a meta-analysis. J Bone Joint Surg Am 82(6):761–773View ArticlePubMedGoogle Scholar
  15. Robbins SE, Hanna AM (1987) Running-related injury prevention through barefoot adaptations. Med Sci Sports Exerc 19(2):148–156View ArticlePubMedGoogle Scholar
  16. Robbins SE, Hanna AM, Gouw GJ (1988) Overload protection avoidance response to heavy plantar surface loading. Med Sci Sports Exerc 20(1):85–92View ArticlePubMedGoogle Scholar
  17. Rolian C, Lieberman DE, Hamill J, Scott JW, Werbel W (2009) Walking, running and the evolution of short toes in humans. J Exp Biol 212(5):713–721View ArticlePubMedGoogle Scholar
  18. Salinero JJ, Abian-Vicen J, Del Coso J, González-Millán C (2014) The influence of ankle dorsiflexion on jumping capacity and the modified agility t-test performance. Eur J Sport Sci 14(2):137–143View ArticlePubMedGoogle Scholar
  19. Shu Y, Mei Q, Fernandez J, Li Z, Feng N, Gu Y (2015) Foot morphological difference between habitually shod and unshod runners. PLoS ONE 10(7):e0131385View ArticlePubMedPubMed CentralGoogle Scholar
  20. Tam N, Wilson JLA, Noakes TD, Tucker R (2014) Barefoot running: an evaluation of current hypothesis, future research and clinical applications. Br J Sports Med 48(5):349–355View ArticlePubMedGoogle Scholar
  21. Taylor DC, Bassett FH (1993) Syndesmosis ankle sprains. Diagnosing the injury and aiding recovery. Phys Sports Med 21(12):39–46Google Scholar
  22. Vint PF, Hinrichs RN (1996) Differences between one-foot and two-foot vertical jump performances. J Appl Biomech 12:338–358View ArticleGoogle Scholar
  23. Williams GN, Jones MH, Amendola A (2007) Syndesmotic ankle sprains in athletes. Am J Sports Med 35(7):1197–1207View ArticlePubMedGoogle Scholar
  24. Wolf S, Simon J, Patikas D, Schuster W, Armbrust P, Döderlein L (2008) Foot motion in children shoes—a comparison of barefoot walking with shod walking in conventional and flexible shoes. Gait Posture 27(1):51–59View ArticlePubMedGoogle Scholar
  25. Wolfe MW, Uhl TL, Mattacola CG, McCluskey LC (2001) Management of ankle sprains. Am Fam Physician 63(1):93–104PubMedGoogle Scholar
  26. Zipfel B, Berger LR (2007) Shod versus unshod: the emergence of forefoot pathology in modern humans. Foot 17(4):205–213View ArticleGoogle Scholar

Copyright

© The Author(s) 2016